io.reactivex.rxjava3.core

Class Maybe<T>

java.lang.Object

io.reactivex.rxjava3.core.Maybe<T>

Type Parameters:

T - the value type

All Implemented Interfaces:

MaybeSource<T>

Direct Known Subclasses:

MaybeSubject

public abstract class Maybe<T>
extends Object
implements MaybeSource<T>

The Maybe class represents a deferred computation and emission of a single value, no value at all or an exception.

The Maybe class implements the MaybeSource base interface and the default consumer type it interacts with is the MaybeObserver via the subscribe(MaybeObserver) method.

The Maybe operates with the following sequential protocol:

     onSubscribe (onSuccess | onError | onComplete)?
 

Note that onSuccess, onError and onComplete are mutually exclusive events; unlike Observable, onSuccess is never followed by onError or onComplete.

Like Observable, a running Maybe can be stopped through the Disposable instance provided to consumers through MaybeObserver.onSubscribe(io.reactivex.rxjava3.disposables.Disposable).

Like an Observable, a Maybe is lazy, can be either "hot" or "cold", synchronous or asynchronous. Maybe instances returned by the methods of this class are cold and there is a standard hot implementation in the form of a subject: MaybeSubject.

The documentation for this class makes use of marble diagrams. The following legend explains these diagrams:

See Flowable or Observable for the implementation of the Reactive Pattern for a stream or vector of values.

Example:

 Disposable d = Maybe.just("Hello World")
    .delay(10, TimeUnit.SECONDS, Schedulers.io())
    .subscribeWith(new DisposableMaybeObserver<String>() {
        @Override
        public void onStart() {
            System.out.println("Started");
        }

        @Override
        public void onSuccess(String value) {
            System.out.println("Success: " + value);
        }

        @Override
        public void onError(Throwable error) {
            error.printStackTrace();
        }

        @Override
        public void onComplete() {
            System.out.println("Done!");
        }
    });
 
 Thread.sleep(5000);
 
 d.dispose();
 

Note that by design, subscriptions via subscribe(MaybeObserver) can't be disposed from the outside (hence the void return of the subscribe(MaybeObserver) method) and it is the responsibility of the implementor of the MaybeObserver to allow this to happen. RxJava supports such usage with the standard DisposableMaybeObserver instance. For convenience, the subscribeWith(MaybeObserver) method is provided as well to allow working with a MaybeObserver (or subclass) instance to be applied with in a fluent manner (such as in the example above).

Since:

2.0

See Also:

DisposableMaybeObserver

Constructor Summary

Constructors

Constructor and Description
Maybe()

Method Summary

Modifier and Type	Method and Description
static <T> @NonNull Maybe<T>	amb(@NonNull Iterable<? extends MaybeSource<? extends T>> sources) Runs multiple MaybeSources provided by an Iterable sequence and signals the events of the first one that signals (disposing the rest).
static <T> @NonNull Maybe<T>	ambArray(MaybeSource<? extends T>... sources) Runs multiple MaybeSources and signals the events of the first one that signals (disposing the rest).
@NonNull Maybe<T>	ambWith(@NonNull MaybeSource<? extends T> other) Mirrors the MaybeSource (current or provided) that first signals an event.
T	blockingGet() Waits in a blocking fashion until the current Maybe signals a success value (which is returned), null if completed or an exception (which is propagated).
T	blockingGet(T defaultValue) Waits in a blocking fashion until the current Maybe signals a success value (which is returned), defaultValue if completed or an exception (which is propagated).
void	blockingSubscribe() Subscribes to the current Maybe and blocks the current thread until it terminates.
void	blockingSubscribe(@NonNull Consumer<? super T> onSuccess) Subscribes to the current Maybe and calls given onSuccess callback on the current thread when it completes normally.
void	blockingSubscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError) Subscribes to the current Maybe and calls the appropriate callback on the current thread when it terminates.
void	blockingSubscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError, @NonNull Action onComplete) Subscribes to the current Maybe and calls the appropriate callback on the current thread when it terminates.
void	blockingSubscribe(@NonNull MaybeObserver<? super T> observer) Subscribes to the current Maybe and calls the appropriate MaybeObserver method on the current thread.
@NonNull Maybe<T>	cache() Returns a Maybe that subscribes to this Maybe lazily, caches its event and replays it, to all the downstream subscribers.
<U> @NonNull Maybe<U>	cast(@NonNull Class<? extends U> clazz) Casts the success value of the current Maybe into the target type or signals a ClassCastException if not compatible.
<R> @NonNull Maybe<R>	compose(@NonNull MaybeTransformer<? super T,? extends R> transformer) Transform a Maybe by applying a particular MaybeTransformer function to it.
static <T> @NonNull Flowable<T>	concat(@NonNull Iterable<? extends MaybeSource<? extends T>> sources) Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources provided by an Iterable sequence as a Flowable sequence.
static <T> @NonNull Flowable<T>	concat(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2) Returns a Flowable that emits the items emitted by two MaybeSources, one after the other.
static <T> @NonNull Flowable<T>	concat(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2, @NonNull MaybeSource<? extends T> source3) Returns a Flowable that emits the items emitted by three MaybeSources, one after the other.
static <T> @NonNull Flowable<T>	concat(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2, @NonNull MaybeSource<? extends T> source3, @NonNull MaybeSource<? extends T> source4) Returns a Flowable that emits the items emitted by four MaybeSources, one after the other.
static <T> @NonNull Flowable<T>	concat(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources provided by a Publisher sequence as a Flowable sequence.
static <T> @NonNull Flowable<T>	concat(@NonNull Publisher<? extends MaybeSource<? extends T>> sources, int prefetch) Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources provided by a Publisher sequence as a Flowable sequence.
static <T> @NonNull Flowable<T>	concatArray(MaybeSource<? extends T>... sources) Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources in the array as a Flowable sequence.
static <T> @NonNull Flowable<T>	concatArrayDelayError(MaybeSource<? extends T>... sources) Concatenates a variable number of MaybeSource sources and delays errors from any of them till all terminate as a Flowable sequence.
static <T> @NonNull Flowable<T>	concatArrayEager(MaybeSource<? extends T>... sources) Concatenates a sequence of MaybeSource eagerly into a Flowable sequence.
static <T> @NonNull Flowable<T>	concatArrayEagerDelayError(MaybeSource<? extends T>... sources) Concatenates a sequence of MaybeSource eagerly into a Flowable sequence.
static <T> @NonNull Flowable<T>	concatDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources) Concatenates the Iterable sequence of MaybeSources into a single sequence by subscribing to each MaybeSource, one after the other, one at a time and delays any errors till the all inner MaybeSources terminate as a Flowable sequence.
static <T> @NonNull Flowable<T>	concatDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Concatenates the Publisher sequence of MaybeSources into a single sequence by subscribing to each inner MaybeSource, one after the other, one at a time and delays any errors till the all inner and the outer Publisher terminate as a Flowable sequence.
static <T> @NonNull Flowable<T>	concatDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources, int prefetch) Concatenates the Publisher sequence of MaybeSources into a single sequence by subscribing to each inner MaybeSource, one after the other, one at a time and delays any errors till the all inner and the outer Publisher terminate as a Flowable sequence.
static <T> @NonNull Flowable<T>	concatEager(@NonNull Iterable<? extends MaybeSource<? extends T>> sources) Concatenates a sequence of MaybeSources eagerly into a Flowable sequence.
static <T> @NonNull Flowable<T>	concatEager(@NonNull Iterable<? extends MaybeSource<? extends T>> sources, int maxConcurrency) Concatenates a sequence of MaybeSources eagerly into a Flowable sequence and runs a limited number of the inner sequences at once.
static <T> @NonNull Flowable<T>	concatEager(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence.
static <T> @NonNull Flowable<T>	concatEager(@NonNull Publisher<? extends MaybeSource<? extends T>> sources, int maxConcurrency) Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence, running at most the given number of inner MaybeSources at once.
static <T> @NonNull Flowable<T>	concatEagerDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources) Concatenates a sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all inner MaybeSources terminate.
static <T> @NonNull Flowable<T>	concatEagerDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources, int maxConcurrency) Concatenates a sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all inner MaybeSources terminate and runs a limited number of inner MaybeSources at once.
static <T> @NonNull Flowable<T>	concatEagerDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all the inner and the outer sequence terminate.
static <T> @NonNull Flowable<T>	concatEagerDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources, int maxConcurrency) Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all the inner and the outer sequence terminate and runs a limited number of the inner MaybeSources at once.
<R> @NonNull Maybe<R>	concatMap(@NonNull Function<? super T,? extends MaybeSource<? extends R>> mapper) Returns a Maybe that is based on applying a specified function to the item emitted by the current Maybe, where that function returns a MaybeSource.
@NonNull Completable	concatMapCompletable(@NonNull Function<? super T,? extends CompletableSource> mapper) Returns a Completable that completes based on applying a specified function to the item emitted by the current Maybe, where that function returns a Completable.
<R> @NonNull Maybe<R>	concatMapSingle(@NonNull Function<? super T,? extends SingleSource<? extends R>> mapper) Returns a Maybe based on applying a specified function to the item emitted by the current Maybe, where that function returns a Single.
@NonNull Flowable<T>	concatWith(@NonNull MaybeSource<? extends T> other) Returns a Flowable that emits the items emitted from the current Maybe, then the other MaybeSource, one after the other, without interleaving them.
@NonNull Single<Boolean>	contains(@NonNull Object item) Returns a Single that emits a Boolean that indicates whether the current Maybe emitted a specified item.
@NonNull Single<Long>	count() Returns a Single that counts the total number of items emitted (0 or 1) by the current Maybe and emits this count as a 64-bit Long.
static <T> @NonNull Maybe<T>	create(@NonNull MaybeOnSubscribe<T> onSubscribe) Provides an API (via a cold Maybe) that bridges the reactive world with the callback-style world.
@NonNull Single<T>	defaultIfEmpty(T defaultItem) Returns a Single that emits the item emitted by the current Maybe or a specified default item if the current Maybe is empty.
static <T> @NonNull Maybe<T>	defer(@NonNull Supplier<? extends MaybeSource<? extends T>> supplier) Calls a Supplier for each individual MaybeObserver to return the actual MaybeSource source to be subscribed to.
@NonNull Maybe<T>	delay(long time, @NonNull TimeUnit unit) Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay.
@NonNull Maybe<T>	delay(long time, @NonNull TimeUnit unit, boolean delayError) Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay.
@NonNull Maybe<T>	delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay.
@NonNull Maybe<T>	delay(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, boolean delayError) Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay running on the specified Scheduler.
<U> @NonNull Maybe<T>	delay(@NonNull Publisher<U> delayIndicator) Delays the emission of this Maybe until the given Publisher signals an item or completes.
@NonNull Maybe<T>	delaySubscription(long time, @NonNull TimeUnit unit) Returns a Maybe that delays the subscription to the current Maybe by a given amount of time.
@NonNull Maybe<T>	delaySubscription(long time, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) Returns a Maybe that delays the subscription to the current Maybe by a given amount of time, both waiting and subscribing on a given Scheduler.
<U> @NonNull Maybe<T>	delaySubscription(@NonNull Publisher<U> subscriptionIndicator) Returns a Maybe that delays the subscription to this Maybe until the other Publisher emits an element or completes normally.
<R> @NonNull Maybe<R>	dematerialize(@NonNull Function<? super T,Notification<R>> selector) Maps the Notification success value of the current Maybe back into normal onSuccess, onError or onComplete signals.
@NonNull Maybe<T>	doAfterSuccess(@NonNull Consumer<? super T> onAfterSuccess) Calls the specified Consumer with the success item after this item has been emitted to the downstream.
@NonNull Maybe<T>	doAfterTerminate(@NonNull Action onAfterTerminate) Registers an Action to be called when this Maybe invokes either onSuccess, onComplete or onError.
@NonNull Maybe<T>	doFinally(@NonNull Action onFinally) Calls the specified action after this Maybe signals onSuccess, onError or onComplete or gets disposed by the downstream.
@NonNull Maybe<T>	doOnComplete(@NonNull Action onComplete) Invokes an Action just before the current Maybe calls onComplete.
@NonNull Maybe<T>	doOnDispose(@NonNull Action onDispose) Calls the shared Action if a MaybeObserver subscribed to the current Maybe disposes the common Disposable it received via onSubscribe.
@NonNull Maybe<T>	doOnError(@NonNull Consumer<? super Throwable> onError) Calls the shared Consumer with the error sent via onError for each MaybeObserver that subscribes to the current Maybe.
@NonNull Maybe<T>	doOnEvent(@NonNull BiConsumer<? super T,? super Throwable> onEvent) Calls the given onEvent callback with the (success value, null) for an onSuccess, (null, throwable) for an onError or (null, null) for an onComplete signal from this Maybe before delivering said signal to the downstream.
@NonNull Maybe<T>	doOnLifecycle(@NonNull Consumer<? super Disposable> onSubscribe, @NonNull Action onDispose) Calls the appropriate onXXX method (shared between all MaybeObservers) for the lifecycle events of the sequence (subscription, disposal).
@NonNull Maybe<T>	doOnSubscribe(@NonNull Consumer<? super Disposable> onSubscribe) Calls the shared Consumer with the Disposable sent through the onSubscribe for each MaybeObserver that subscribes to the current Maybe.
@NonNull Maybe<T>	doOnSuccess(@NonNull Consumer<? super T> onSuccess) Calls the shared Consumer with the success value sent via onSuccess for each MaybeObserver that subscribes to the current Maybe.
@NonNull Maybe<T>	doOnTerminate(@NonNull Action onTerminate) Returns a Maybe instance that calls the given onTerminate callback just before this Maybe completes normally or with an exception.
static <T> @NonNull Maybe<T>	empty() Returns a (singleton) Maybe instance that calls onComplete immediately.
static <T> @NonNull Maybe<T>	error(@NonNull Supplier<? extends Throwable> supplier) Returns a Maybe that invokes a MaybeObserver's onError method when the MaybeObserver subscribes to it.
static <T> @NonNull Maybe<T>	error(@NonNull Throwable throwable) Returns a Maybe that invokes a subscriber's onError method when the subscriber subscribes to it.
@NonNull Maybe<T>	filter(@NonNull Predicate<? super T> predicate) Filters the success item of the Maybe via a predicate function and emitting it if the predicate returns true, completing otherwise.
<R> @NonNull Maybe<R>	flatMap(@NonNull Function<? super T,? extends MaybeSource<? extends R>> mapper) Returns a Maybe that is based on applying a specified function to the item emitted by the current Maybe, where that function returns a MaybeSource.
<R> @NonNull Maybe<R>	flatMap(@NonNull Function<? super T,? extends MaybeSource<? extends R>> onSuccessMapper, @NonNull Function<? super Throwable,? extends MaybeSource<? extends R>> onErrorMapper, @NonNull Supplier<? extends MaybeSource<? extends R>> onCompleteSupplier) Maps the onSuccess, onError or onComplete signals of the current Maybe into a MaybeSource and emits that MaybeSource's signals.
<U,R> @NonNull Maybe<R>	flatMap(@NonNull Function<? super T,? extends MaybeSource<? extends U>> mapper, @NonNull BiFunction<? super T,? super U,? extends R> combiner) Returns a Maybe that emits the results of a specified function to the pair of values emitted by the current Maybe and a specified mapped MaybeSource.
@NonNull Completable	flatMapCompletable(@NonNull Function<? super T,? extends CompletableSource> mapper) Returns a Completable that completes based on applying a specified function to the item emitted by the current Maybe, where that function returns a Completable.
<R> @NonNull Observable<R>	flatMapObservable(@NonNull Function<? super T,? extends ObservableSource<? extends R>> mapper) Returns an Observable that is based on applying a specified function to the item emitted by the current Maybe, where that function returns an ObservableSource.
<R> @NonNull Flowable<R>	flatMapPublisher(@NonNull Function<? super T,? extends Publisher<? extends R>> mapper) Returns a Flowable that emits items based on applying a specified function to the item emitted by the current Maybe, where that function returns a Publisher.
<R> @NonNull Maybe<R>	flatMapSingle(@NonNull Function<? super T,? extends SingleSource<? extends R>> mapper) Returns a Maybe based on applying a specified function to the item emitted by the current Maybe, where that function returns a Single.
<U> @NonNull Flowable<U>	flattenAsFlowable(@NonNull Function<? super T,? extends Iterable<? extends U>> mapper) Maps the success value of the current Maybe into an Iterable and emits its items as a Flowable sequence.
<U> @NonNull Observable<U>	flattenAsObservable(@NonNull Function<? super T,? extends Iterable<? extends U>> mapper) Maps the success value of the current Maybe into an Iterable and emits its items as an Observable sequence.
<R> @NonNull Flowable<R>	flattenStreamAsFlowable(@NonNull Function<? super T,? extends Stream<? extends R>> mapper) Maps the upstream succecss value into a Java Stream and emits its items to the downstream consumer as a Flowable.
<R> @NonNull Observable<R>	flattenStreamAsObservable(@NonNull Function<? super T,? extends Stream<? extends R>> mapper) Maps the upstream succecss value into a Java Stream and emits its items to the downstream consumer as an Observable.
static <T> @NonNull Maybe<T>	fromAction(@NonNull Action action) Returns a Maybe instance that runs the given Action for each MaybeObserver and emits either its exception or simply completes.
static <T> @NonNull Maybe<T>	fromCallable(@NonNull Callable<? extends T> callable) Returns a Maybe that invokes the given Callable for each individual MaybeObserver that subscribes and emits the resulting non-null item via onSuccess while considering a null result from the Callable as indication for valueless completion via onComplete.
static <T> @NonNull Maybe<T>	fromCompletable(@NonNull CompletableSource completableSource) Wraps a CompletableSource into a Maybe.
static <T> @NonNull Maybe<T>	fromCompletionStage(@NonNull CompletionStage<T> stage) Signals the completion value or error of the given (hot) CompletionStage-based asynchronous calculation.
static <T> @NonNull Maybe<T>	fromFuture(@NonNull Future<? extends T> future) Converts a Future into a Maybe, treating a null result as an indication of emptiness.
static <T> @NonNull Maybe<T>	fromFuture(@NonNull Future<? extends T> future, long timeout, @NonNull TimeUnit unit) Converts a Future into a Maybe, with a timeout on the Future.
static <T> @NonNull Maybe<T>	fromObservable(@NonNull ObservableSource<T> source) Wraps an ObservableSource into a Maybe and emits the very first item or completes if the source is empty.
static <T> @NonNull Maybe<T>	fromOptional(@NonNull Optional<T> optional) Converts the existing value of the provided optional into a just(Object) or an empty optional into an empty() Maybe instance.
static <T> @NonNull Maybe<T>	fromPublisher(@NonNull Publisher<T> source) Wraps a Publisher into a Maybe and emits the very first item or completes if the source is empty.
static <T> @NonNull Maybe<T>	fromRunnable(@NonNull Runnable run) Returns a Maybe instance that runs the given Runnable for each MaybeObserver and emits either its unchecked exception or simply completes.
static <T> @NonNull Maybe<T>	fromSingle(@NonNull SingleSource<T> single) Wraps a SingleSource into a Maybe.
static <T> @NonNull Maybe<T>	fromSupplier(@NonNull Supplier<? extends T> supplier) Returns a Maybe that invokes the given Supplier for each individual MaybeObserver that subscribes and emits the resulting non-null item via onSuccess while considering a null result from the Supplier as indication for valueless completion via onComplete.
@NonNull Maybe<T>	hide() Hides the identity of this Maybe and its Disposable.
@NonNull Completable	ignoreElement() Returns a Completable that ignores the item emitted by the current Maybe and only calls onComplete or onError.
@NonNull Single<Boolean>	isEmpty() Returns a Single that emits true if the current Maybe is empty, otherwise false.
static <T> @NonNull Maybe<T>	just(T item) Returns a Maybe that emits a specified item.
<R> @NonNull Maybe<R>	lift(@NonNull MaybeOperator<? extends R,? super T> lift) This method requires advanced knowledge about building operators, please consider other standard composition methods first; Returns a Maybe which, when subscribed to, invokes the apply(MaybeObserver) method of the provided MaybeOperator for each individual downstream Maybe and allows the insertion of a custom operator by accessing the downstream's MaybeObserver during this subscription phase and providing a new MaybeObserver, containing the custom operator's intended business logic, that will be used in the subscription process going further upstream.
<R> @NonNull Maybe<R>	map(@NonNull Function<? super T,? extends R> mapper) Returns a Maybe that applies a specified function to the item emitted by the current Maybe and emits the result of this function application.
<R> @NonNull Maybe<R>	mapOptional(@NonNull Function<? super T,Optional<? extends R>> mapper) Maps the upstream success value into an Optional and emits the contained item if not empty.
@NonNull Single<Notification<T>>	materialize() Maps the signal types of this Maybe into a Notification of the same kind and emits it as a Single's onSuccess value to downstream.
static <T> @NonNull Flowable<T>	merge(@NonNull Iterable<? extends MaybeSource<? extends T>> sources) Merges an Iterable sequence of MaybeSource instances into a single Flowable sequence, running all MaybeSources at once.
static <T> @NonNull Maybe<T>	merge(@NonNull MaybeSource<? extends MaybeSource<? extends T>> source) Flattens a MaybeSource that emits a MaybeSource into a single MaybeSource that emits the item emitted by the nested MaybeSource, without any transformation.
static <T> @NonNull Flowable<T>	merge(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2) Flattens two MaybeSources into a single Flowable, without any transformation.
static <T> @NonNull Flowable<T>	merge(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2, @NonNull MaybeSource<? extends T> source3) Flattens three MaybeSources into a single Flowable, without any transformation.
static <T> @NonNull Flowable<T>	merge(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2, @NonNull MaybeSource<? extends T> source3, @NonNull MaybeSource<? extends T> source4) Flattens four MaybeSources into a single Flowable, without any transformation.
static <T> @NonNull Flowable<T>	merge(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Merges a Publisher sequence of MaybeSource instances into a single Flowable sequence, running all MaybeSources at once.
static <T> @NonNull Flowable<T>	merge(@NonNull Publisher<? extends MaybeSource<? extends T>> sources, int maxConcurrency) Merges a Publisher sequence of MaybeSource instances into a single Flowable sequence, running at most maxConcurrency MaybeSources at once.
static <T> @NonNull Flowable<T>	mergeArray(MaybeSource<? extends T>... sources) Merges an array of MaybeSource instances into a single Flowable sequence, running all MaybeSources at once.
static <T> @NonNull Flowable<T>	mergeArrayDelayError(MaybeSource<? extends T>... sources) Flattens an array of MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from each of the source MaybeSources without being interrupted by an error notification from one of them.
static <T> @NonNull Flowable<T>	mergeDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources) Flattens an Iterable sequence of MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from each of the source MaybeSources without being interrupted by an error notification from one of them.
static <T> @NonNull Flowable<T>	mergeDelayError(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2) Flattens two MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from each of the source MaybeSources without being interrupted by an error notification from one of them.
static <T> @NonNull Flowable<T>	mergeDelayError(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2, @NonNull MaybeSource<? extends T> source3) Flattens three MaybeSource into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them.
static <T> @NonNull Flowable<T>	mergeDelayError(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2, @NonNull MaybeSource<? extends T> source3, @NonNull MaybeSource<? extends T> source4) Flattens four MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them.
static <T> @NonNull Flowable<T>	mergeDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Flattens a Publisher that emits MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them or even the main Publisher.
static <T> @NonNull Flowable<T>	mergeDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources, int maxConcurrency) Flattens a Publisher that emits MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them or even the main Publisher as well as limiting the total number of active MaybeSources.
@NonNull Flowable<T>	mergeWith(@NonNull MaybeSource<? extends T> other) Flattens this Maybe and another MaybeSource into a single Flowable, without any transformation.
static <T> @NonNull Maybe<T>	never() Returns a Maybe that never sends any items or notifications to a MaybeObserver.
@NonNull Maybe<T>	observeOn(@NonNull Scheduler scheduler) Wraps a Maybe to emit its item (or notify of its error) on a specified Scheduler, asynchronously.
<U> @NonNull Maybe<U>	ofType(@NonNull Class<U> clazz) Filters the items emitted by the current Maybe, only emitting its success value if that is an instance of the supplied Class.
@NonNull Maybe<T>	onErrorComplete() Returns a Maybe instance that if this Maybe emits an error, it will emit an onComplete and swallow the throwable.
@NonNull Maybe<T>	onErrorComplete(@NonNull Predicate<? super Throwable> predicate) Returns a Maybe instance that if this Maybe emits an error and the predicate returns true, it will emit an onComplete and swallow the throwable.
@NonNull Maybe<T>	onErrorResumeNext(@NonNull Function<? super Throwable,? extends MaybeSource<? extends T>> fallbackSupplier) Resumes the flow with a MaybeSource returned for the failure Throwable of the current Maybe by a function instead of signaling the error via onError.
@NonNull Maybe<T>	onErrorResumeWith(@NonNull MaybeSource<? extends T> fallback) Resumes the flow with the given MaybeSource when the current Maybe fails instead of signaling the error via onError.
@NonNull Maybe<T>	onErrorReturn(@NonNull Function<? super Throwable,? extends T> itemSupplier) Ends the flow with a success item returned by a function for the Throwable error signaled by the current Maybe instead of signaling the error via onError.
@NonNull Maybe<T>	onErrorReturnItem(T item) Ends the flow with the given success item when the current Maybe fails instead of signaling the error via onError.
@NonNull Maybe<T>	onTerminateDetach() Nulls out references to the upstream producer and downstream MaybeObserver if the sequence is terminated or downstream calls dispose().
@NonNull Flowable<T>	repeat() Returns a Flowable that repeats the sequence of items emitted by the current Maybe indefinitely.
@NonNull Flowable<T>	repeat(long times) Returns a Flowable that repeats the sequence of items emitted by the current Maybe at most count times.
@NonNull Flowable<T>	repeatUntil(@NonNull BooleanSupplier stop) Returns a Flowable that repeats the sequence of items emitted by the current Maybe until the provided stop function returns true.
@NonNull Flowable<T>	repeatWhen(@NonNull Function<? super Flowable<Object>,? extends Publisher<?>> handler) Returns a Flowable that emits the same values as the current Maybe with the exception of an onComplete.
@NonNull Maybe<T>	retry() Returns a Maybe that mirrors the current Maybe, resubscribing to it if it calls onError (infinite retry count).
@NonNull Maybe<T>	retry(@NonNull BiPredicate<? super Integer,? super Throwable> predicate) Returns a Maybe that mirrors the current Maybe, resubscribing to it if it calls onError and the predicate returns true for that specific exception and retry count.
@NonNull Maybe<T>	retry(long times) Returns a Maybe that mirrors the current Maybe, resubscribing to it if it calls onError up to a specified number of retries.
@NonNull Maybe<T>	retry(long times, @NonNull Predicate<? super Throwable> predicate) Retries at most times or until the predicate returns false, whichever happens first.
@NonNull Maybe<T>	retry(@NonNull Predicate<? super Throwable> predicate) Retries the current Maybe if it fails and the predicate returns true.
@NonNull Maybe<T>	retryUntil(@NonNull BooleanSupplier stop) Retries until the given stop function returns true.
@NonNull Maybe<T>	retryWhen(@NonNull Function<? super Flowable<Throwable>,? extends Publisher<?>> handler) Returns a Maybe that emits the same values as the current Maybe with the exception of an onError.
void	safeSubscribe(@NonNull MaybeObserver<? super T> observer) Wraps the given MaybeObserver, catches any RuntimeExceptions thrown by its MaybeObserver.onSubscribe(Disposable), MaybeObserver.onSuccess(Object), MaybeObserver.onError(Throwable) or MaybeObserver.onComplete() methods and routes those to the global error handler via RxJavaPlugins.onError(Throwable).
static <T> @NonNull Single<Boolean>	sequenceEqual(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2) Returns a Single that emits a Boolean value that indicates whether two MaybeSource sequences are the same by comparing the items emitted by each MaybeSource pairwise.
static <T> @NonNull Single<Boolean>	sequenceEqual(@NonNull MaybeSource<? extends T> source1, @NonNull MaybeSource<? extends T> source2, @NonNull BiPredicate<? super T,? super T> isEqual) Returns a Single that emits a Boolean value that indicates whether two MaybeSources are the same by comparing the items emitted by each MaybeSource pairwise based on the results of a specified equality function.
@NonNull Flowable<T>	startWith(@NonNull CompletableSource other) Returns a Flowable which first runs the other CompletableSource then the current Maybe if the other completed normally.
@NonNull Flowable<T>	startWith(@NonNull MaybeSource<T> other) Returns a Flowable which first runs the other MaybeSource then the current Maybe if the other succeeded or completed normally.
@NonNull Observable<T>	startWith(@NonNull ObservableSource<T> other) Returns an Observable which first delivers the events of the other ObservableSource then runs the current Maybe.
@NonNull Flowable<T>	startWith(@NonNull Publisher<T> other) Returns a Flowable which first delivers the events of the other Publisher then runs the current Maybe.
@NonNull Flowable<T>	startWith(@NonNull SingleSource<T> other) Returns a Flowable which first runs the other SingleSource then the current Maybe if the other succeeded normally.
@NonNull Disposable	subscribe() Subscribes to a Maybe and ignores onSuccess and onComplete emissions.
@NonNull Disposable	subscribe(@NonNull Consumer<? super T> onSuccess) Subscribes to a Maybe and provides a callback to handle the items it emits.
@NonNull Disposable	subscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError) Subscribes to a Maybe and provides callbacks to handle the items it emits and any error notification it issues.
@NonNull Disposable	subscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError, @NonNull Action onComplete) Subscribes to a Maybe and provides callbacks to handle the items it emits and any error or completion notification it issues.
@NonNull Disposable	subscribe(@NonNull Consumer<? super T> onSuccess, @NonNull Consumer<? super Throwable> onError, @NonNull Action onComplete, @NonNull DisposableContainer container) Wraps the given onXXX callbacks into a Disposable MaybeObserver, adds it to the given DisposableContainer and ensures, that if the upstream terminates or this particular Disposable is disposed, the MaybeObserver is removed from the given composite.
void	subscribe(@NonNull MaybeObserver<? super T> observer) Subscribes the given MaybeObserver to this MaybeSource instance.
protected abstract void	subscribeActual(@NonNull MaybeObserver<? super T> observer) Implement this method in subclasses to handle the incoming MaybeObservers.
@NonNull Maybe<T>	subscribeOn(@NonNull Scheduler scheduler) Asynchronously subscribes subscribers to this Maybe on the specified Scheduler.
<E extends MaybeObserver<? super T>> E	subscribeWith(E observer) Subscribes a given MaybeObserver (subclass) to this Maybe and returns the given MaybeObserver as is.
@NonNull Maybe<T>	switchIfEmpty(@NonNull MaybeSource<? extends T> other) Returns a Maybe that emits the items emitted by the current Maybe or the items of an alternate MaybeSource if the current Maybe is empty.
@NonNull Single<T>	switchIfEmpty(@NonNull SingleSource<? extends T> other) Returns a Single that emits the items emitted by the current Maybe or the item of an alternate SingleSource if the current Maybe is empty.
static <T> @NonNull Flowable<T>	switchOnNext(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Switches between MaybeSources emitted by the source Publisher whenever a new MaybeSource is emitted, disposing the previously running MaybeSource, exposing the success items as a Flowable sequence.
static <T> @NonNull Flowable<T>	switchOnNextDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources) Switches between MaybeSources emitted by the source Publisher whenever a new MaybeSource is emitted, disposing the previously running MaybeSource, exposing the success items as a Flowable sequence and delaying all errors from all of them until all terminate.
<U> @NonNull Maybe<T>	takeUntil(@NonNull MaybeSource<U> other) Returns a Maybe that emits the items emitted by the current Maybe until a second MaybeSource emits an item.
<U> @NonNull Maybe<T>	takeUntil(@NonNull Publisher<U> other) Returns a Maybe that emits the item emitted by the current Maybe until a second Publisher emits an item.
@NonNull TestObserver<T>	test() Creates a TestObserver and subscribes it to this Maybe.
@NonNull TestObserver<T>	test(boolean dispose) Creates a TestObserver optionally in cancelled state, then subscribes it to this Maybe.
@NonNull Maybe<Timed<T>>	timeInterval() Measures the time (in milliseconds) between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.
@NonNull Maybe<Timed<T>>	timeInterval(@NonNull Scheduler scheduler) Measures the time (in milliseconds) between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.
@NonNull Maybe<Timed<T>>	timeInterval(@NonNull TimeUnit unit) Measures the time between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.
@NonNull Maybe<Timed<T>>	timeInterval(@NonNull TimeUnit unit, @NonNull Scheduler scheduler) Measures the time between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.
@NonNull Maybe<T>	timeout(long timeout, @NonNull TimeUnit unit) Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item.
@NonNull Maybe<T>	timeout(long timeout, @NonNull TimeUnit unit, @NonNull MaybeSource<? extends T> fallback) Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item.
@NonNull Maybe<T>	timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item, where this policy is governed on a specified Scheduler.
@NonNull Maybe<T>	timeout(long timeout, @NonNull TimeUnit unit, @NonNull Scheduler scheduler, @NonNull MaybeSource<? extends T> fallback) Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item using a specified Scheduler.
<U> @NonNull Maybe<T>	timeout(@NonNull MaybeSource<U> timeoutIndicator) If the current Maybe didn't signal an event before the timeoutIndicator MaybeSource signals, a TimeoutException is signaled instead.
<U> @NonNull Maybe<T>	timeout(@NonNull MaybeSource<U> timeoutIndicator, @NonNull MaybeSource<? extends T> fallback) If the current Maybe didn't signal an event before the timeoutIndicator MaybeSource signals, the current Maybe is disposed and the fallback MaybeSource subscribed to as a continuation.
<U> @NonNull Maybe<T>	timeout(@NonNull Publisher<U> timeoutIndicator) If the current Maybe source didn't signal an event before the timeoutIndicator Publisher signals, a TimeoutException is signaled instead.
<U> @NonNull Maybe<T>	timeout(@NonNull Publisher<U> timeoutIndicator, @NonNull MaybeSource<? extends T> fallback) If the current Maybe didn't signal an event before the timeoutIndicator Publisher signals, the current Maybe is disposed and the fallback MaybeSource subscribed to as a continuation.
static @NonNull Maybe<Long>	timer(long delay, @NonNull TimeUnit unit) Returns a Maybe that emits 0L after a specified delay.
static @NonNull Maybe<Long>	timer(long delay, @NonNull TimeUnit unit, @NonNull Scheduler scheduler) Returns a Maybe that emits 0L after a specified delay on a specified Scheduler.
@NonNull Maybe<Timed<T>>	timestamp() Combines the success value from the current Maybe with the current time (in milliseconds) of its reception, using the computation Scheduler as time source, then signals them as a Timed instance.
@NonNull Maybe<Timed<T>>	timestamp(@NonNull Scheduler scheduler) Combines the success value from the current Maybe with the current time (in milliseconds) of its reception, using the given Scheduler as time source, then signals them as a Timed instance.
@NonNull Maybe<Timed<T>>	timestamp(@NonNull TimeUnit unit) Combines the success value from the current Maybe with the current time of its reception, using the computation Scheduler as time source, then signals it as a Timed instance.
@NonNull Maybe<Timed<T>>	timestamp(@NonNull TimeUnit unit, @NonNull Scheduler scheduler) Combines the success value from the current Maybe with the current time of its reception, using the given Scheduler as time source, then signals it as a Timed instance.
<R> R	to(@NonNull MaybeConverter<T,? extends R> converter) Calls the specified converter function during assembly time and returns its resulting value.
@NonNull CompletionStage<T>	toCompletionStage() Signals the upstream success item (or a NoSuchElementException if the upstream is empty) via a CompletionStage.
@NonNull CompletionStage<T>	toCompletionStage(T defaultItem) Signals the upstream success item (or the default item if the upstream is empty) via a CompletionStage.
@NonNull Flowable<T>	toFlowable() Converts this Maybe into a backpressure-aware Flowable instance composing cancellation through.
@NonNull Future<T>	toFuture() Returns a Future representing the single value emitted by the current Maybe or null if the current Maybe is empty.
@NonNull Observable<T>	toObservable() Converts this Maybe into an Observable instance composing disposal through.
@NonNull Single<T>	toSingle() Converts this Maybe into a Single instance composing disposal through and turning an empty Maybe into a signal of NoSuchElementException.
static <T> @NonNull Maybe<T>	unsafeCreate(@NonNull MaybeSource<T> onSubscribe) Advanced use only: creates a Maybe instance without any safeguards by using a callback that is called with a MaybeObserver.
@NonNull Maybe<T>	unsubscribeOn(@NonNull Scheduler scheduler) Returns a Maybe which makes sure when a MaybeObserver disposes the Disposable, that call is propagated up on the specified Scheduler.
static <T,D> @NonNull Maybe<T>	using(@NonNull Supplier<? extends D> resourceSupplier, @NonNull Function<? super D,? extends MaybeSource<? extends T>> sourceSupplier, @NonNull Consumer<? super D> resourceCleanup) Constructs a Maybe that creates a dependent resource object which is disposed of when the generated MaybeSource terminates or the downstream calls dispose().
static <T,D> @NonNull Maybe<T>	using(@NonNull Supplier<? extends D> resourceSupplier, @NonNull Function<? super D,? extends MaybeSource<? extends T>> sourceSupplier, @NonNull Consumer<? super D> resourceCleanup, boolean eager) Constructs a Maybe that creates a dependent resource object which is disposed first ({code eager == true}) when the generated MaybeSource terminates or the downstream disposes; or after ({code eager == false}).
static <T> @NonNull Maybe<T>	wrap(@NonNull MaybeSource<T> source) Wraps a MaybeSource instance into a new Maybe instance if not already a Maybe instance.
static <T,R> @NonNull Maybe<R>	zip(@NonNull Iterable<? extends MaybeSource<? extends T>> sources, @NonNull Function<? super Object[],? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of items emitted, in sequence, by an Iterable of other MaybeSources.
static <T1,T2,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull BiFunction<? super T1,? super T2,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of two items emitted, in sequence, by two other MaybeSources.
static <T1,T2,T3,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull MaybeSource<? extends T3> source3, @NonNull Function3<? super T1,? super T2,? super T3,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of three items emitted, in sequence, by three other MaybeSources.
static <T1,T2,T3,T4,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull MaybeSource<? extends T3> source3, @NonNull MaybeSource<? extends T4> source4, @NonNull Function4<? super T1,? super T2,? super T3,? super T4,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of four items emitted, in sequence, by four other MaybeSources.
static <T1,T2,T3,T4,T5,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull MaybeSource<? extends T3> source3, @NonNull MaybeSource<? extends T4> source4, @NonNull MaybeSource<? extends T5> source5, @NonNull Function5<? super T1,? super T2,? super T3,? super T4,? super T5,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of five items emitted, in sequence, by five other MaybeSources.
static <T1,T2,T3,T4,T5,T6,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull MaybeSource<? extends T3> source3, @NonNull MaybeSource<? extends T4> source4, @NonNull MaybeSource<? extends T5> source5, @NonNull MaybeSource<? extends T6> source6, @NonNull Function6<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of six items emitted, in sequence, by six other MaybeSources.
static <T1,T2,T3,T4,T5,T6,T7,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull MaybeSource<? extends T3> source3, @NonNull MaybeSource<? extends T4> source4, @NonNull MaybeSource<? extends T5> source5, @NonNull MaybeSource<? extends T6> source6, @NonNull MaybeSource<? extends T7> source7, @NonNull Function7<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? super T7,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of seven items emitted, in sequence, by seven other MaybeSources.
static <T1,T2,T3,T4,T5,T6,T7,T8,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull MaybeSource<? extends T3> source3, @NonNull MaybeSource<? extends T4> source4, @NonNull MaybeSource<? extends T5> source5, @NonNull MaybeSource<? extends T6> source6, @NonNull MaybeSource<? extends T7> source7, @NonNull MaybeSource<? extends T8> source8, @NonNull Function8<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? super T7,? super T8,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of eight items emitted, in sequence, by eight other MaybeSources.
static <T1,T2,T3,T4,T5,T6,T7,T8,T9,R> @NonNull Maybe<R>	zip(@NonNull MaybeSource<? extends T1> source1, @NonNull MaybeSource<? extends T2> source2, @NonNull MaybeSource<? extends T3> source3, @NonNull MaybeSource<? extends T4> source4, @NonNull MaybeSource<? extends T5> source5, @NonNull MaybeSource<? extends T6> source6, @NonNull MaybeSource<? extends T7> source7, @NonNull MaybeSource<? extends T8> source8, @NonNull MaybeSource<? extends T9> source9, @NonNull Function9<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? super T7,? super T8,? super T9,? extends R> zipper) Returns a Maybe that emits the results of a specified combiner function applied to combinations of nine items emitted, in sequence, by nine other MaybeSources.
static <T,R> @NonNull Maybe<R>	zipArray(@NonNull Function<? super Object[],? extends R> zipper, MaybeSource<? extends T>... sources) Returns a Maybe that emits the results of a specified combiner function applied to combinations of items emitted, in sequence, by an array of other MaybeSources.
<U,R> @NonNull Maybe<R>	zipWith(@NonNull MaybeSource<? extends U> other, @NonNull BiFunction<? super T,? super U,? extends R> zipper) Waits until this and the other MaybeSource signal a success value then applies the given BiFunction to those values and emits the BiFunction's resulting value to downstream.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Maybe

public Maybe()

Method Detail

amb

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> amb(@NonNull Iterable<? extends MaybeSource<? extends T>> sources)

Runs multiple MaybeSources provided by an Iterable sequence and signals the events of the first one that signals (disposing the rest).

Scheduler:

amb does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - the Iterable sequence of sources. A subscription to each source will occur in the same order as in the Iterable.

Returns:

the new Maybe instance

Throws:

NullPointerException - if sources is null

ambArray

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
 @SafeVarargs
public static <T> @NonNull Maybe<T> ambArray(@NonNull MaybeSource<? extends T>... sources)

Runs multiple MaybeSources and signals the events of the first one that signals (disposing the rest).

Scheduler:

ambArray does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - the array of sources. A subscription to each source will occur in the same order as in the array.

Returns:

the new Maybe instance

Throws:

NullPointerException - if sources is null

concat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> concat(@NonNull Iterable<? extends MaybeSource<? extends T>> sources)

Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources provided by an Iterable sequence as a Flowable sequence.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

concat does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - the Iterable sequence of MaybeSource instances

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

concat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> concat(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2)

Returns a Flowable that emits the items emitted by two MaybeSources, one after the other.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

concat does not operate by default on a particular Scheduler.

Type Parameters:

T - the common value type

Parameters:

source1 - a MaybeSource to be concatenated

source2 - a MaybeSource to be concatenated

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1 or source2 is null

See Also:

ReactiveX operators documentation: Concat

concat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> concat(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2,
        @NonNull MaybeSource<? extends T> source3)

Returns a Flowable that emits the items emitted by three MaybeSources, one after the other.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

concat does not operate by default on a particular Scheduler.

Type Parameters:

T - the common value type

Parameters:

source1 - a MaybeSource to be concatenated

source2 - a MaybeSource to be concatenated

source3 - a MaybeSource to be concatenated

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1, source2 or source3 is null

See Also:

ReactiveX operators documentation: Concat

concat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> concat(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2,
        @NonNull MaybeSource<? extends T> source3,
        @NonNull MaybeSource<? extends T> source4)

Returns a Flowable that emits the items emitted by four MaybeSources, one after the other.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

concat does not operate by default on a particular Scheduler.

Type Parameters:

T - the common value type

Parameters:

source1 - a MaybeSource to be concatenated

source2 - a MaybeSource to be concatenated

source3 - a MaybeSource to be concatenated

source4 - a MaybeSource to be concatenated

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1, source2, source3 or source4 is null

See Also:

ReactiveX operators documentation: Concat

concat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concat(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources provided by a Publisher sequence as a Flowable sequence.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer and expects the Publisher to honor backpressure as well. If the sources Publisher violates this, a MissingBackpressureException is signaled.

Scheduler:

concat does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - the Publisher of MaybeSource instances

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

concat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> concat(@NonNull Publisher<? extends MaybeSource<? extends T>> sources,
        int prefetch)

Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources provided by a Publisher sequence as a Flowable sequence.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer and expects the Publisher to honor backpressure as well. If the sources Publisher violates this, a MissingBackpressureException is signaled.

Scheduler:

concat does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - the Publisher of MaybeSource instances

prefetch - the number of MaybeSources to prefetch from the Publisher

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if prefetch is non-positive

concatArray

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @SafeVarargs
public static <T> @NonNull Flowable<T> concatArray(@NonNull MaybeSource<? extends T>... sources)

Concatenate the single values, in a non-overlapping fashion, of the MaybeSource sources in the array as a Flowable sequence.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

concatArray does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - the array of MaybeSource instances

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

concatArrayDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @SafeVarargs
 @NonNull
public static <T> @NonNull Flowable<T> concatArrayDelayError(@NonNull MaybeSource<? extends T>... sources)

Concatenates a variable number of MaybeSource sources and delays errors from any of them till all terminate as a Flowable sequence.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

concatArrayDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common base value type

Parameters:

sources - the array of sources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

concatArrayEager

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
 @SafeVarargs
public static <T> @NonNull Flowable<T> concatArrayEager(@NonNull MaybeSource<? extends T>... sources)

Concatenates a sequence of MaybeSource eagerly into a Flowable sequence.

Eager concatenation means that once an observer subscribes, this operator subscribes to all of the source MaybeSources. The operator buffers the value emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSources that need to be eagerly concatenated

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

concatArrayEagerDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
 @SafeVarargs
public static <T> @NonNull Flowable<T> concatArrayEagerDelayError(@NonNull MaybeSource<? extends T>... sources)

Concatenates a sequence of MaybeSource eagerly into a Flowable sequence.

Eager concatenation means that once an observer subscribes, this operator subscribes to all of the source MaybeSources. The operator buffers the value emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSources that need to be eagerly concatenated

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

Since:

3.0.0

concatDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> concatDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources)

Concatenates the Iterable sequence of MaybeSources into a single sequence by subscribing to each MaybeSource, one after the other, one at a time and delays any errors till the all inner MaybeSources terminate as a Flowable sequence.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

concatDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

sources - the Iterable sequence of MaybeSources

Returns:

the new Flowable with the concatenating behavior

Throws:

NullPointerException - if sources is null

concatDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Concatenates the Publisher sequence of MaybeSources into a single sequence by subscribing to each inner MaybeSource, one after the other, one at a time and delays any errors till the all inner and the outer Publisher terminate as a Flowable sequence.

Backpressure:

concatDelayError fully supports backpressure.

Scheduler:

concatDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

sources - the Publisher sequence of MaybeSources

Returns:

the new Flowable with the concatenating behavior

Throws:

NullPointerException - if sources is null

concatDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources,
        int prefetch)

Concatenates the Publisher sequence of MaybeSources into a single sequence by subscribing to each inner MaybeSource, one after the other, one at a time and delays any errors till the all inner and the outer Publisher terminate as a Flowable sequence.

Backpressure:

concatDelayError fully supports backpressure.

Scheduler:

concatDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

sources - the Publisher sequence of MaybeSources

prefetch - The number of upstream items to prefetch so that fresh items are ready to be mapped when a previous MaybeSource terminates. The operator replenishes after half of the prefetch amount has been consumed and turned into MaybeSources.

Returns:

the new Flowable with the concatenating behavior

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if prefetch is non-positive

Since:

3.0.0

concatEager

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEager(@NonNull Iterable<? extends MaybeSource<? extends T>> sources)

Concatenates a sequence of MaybeSources eagerly into a Flowable sequence.

Eager concatenation means that once an observer subscribes, this operator subscribes to all of the source MaybeSources. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSource that need to be eagerly concatenated

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

concatEager

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEager(@NonNull Iterable<? extends MaybeSource<? extends T>> sources,
        int maxConcurrency)

Concatenates a sequence of MaybeSources eagerly into a Flowable sequence and runs a limited number of the inner sequences at once.

Eager concatenation means that once an observer subscribes, this operator subscribes to all of the source MaybeSources. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSource that need to be eagerly concatenated

maxConcurrency - the maximum number of concurrently running inner MaybeSources; Integer.MAX_VALUE is interpreted as all inner MaybeSources can be active at the same time

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if maxConcurrency is non-positive

Since:

3.0.0

concatEager

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEager(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence.

Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the emitted source MaybeSources as they are observed. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream and the outer Publisher is expected to support backpressure. Violating this assumption, the operator will signal MissingBackpressureException.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSources that need to be eagerly concatenated

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

concatEager

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEager(@NonNull Publisher<? extends MaybeSource<? extends T>> sources,
        int maxConcurrency)

Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence, running at most the given number of inner MaybeSources at once.

Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the emitted source MaybeSources as they are observed. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream and the outer Publisher is expected to support backpressure. Violating this assumption, the operator will signal MissingBackpressureException.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSources that need to be eagerly concatenated

maxConcurrency - the maximum number of concurrently running inner MaybeSources; Integer.MAX_VALUE is interpreted as all inner MaybeSources can be active at the same time

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if maxConcurrency is non-positive

Since:

3.0.0

concatEagerDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEagerDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources)

Concatenates a sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all inner MaybeSources terminate.

Eager concatenation means that once an observer subscribes, this operator subscribes to all of the source MaybeSources. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSource that need to be eagerly concatenated

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

Since:

3.0.0

concatEagerDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEagerDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources,
        int maxConcurrency)

Concatenates a sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all inner MaybeSources terminate and runs a limited number of inner MaybeSources at once.

Eager concatenation means that once an observer subscribes, this operator subscribes to all of the source MaybeSources. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSource that need to be eagerly concatenated

maxConcurrency - the maximum number of concurrently running inner MaybeSources; Integer.MAX_VALUE is interpreted as all inner MaybeSources can be active at the same time

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if maxConcurrency is non-positive

Since:

3.0.0

concatEagerDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEagerDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all the inner and the outer sequence terminate.

Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the emitted source MaybeSources as they are observed. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream and the outer Publisher is expected to support backpressure. Violating this assumption, the operator will signal MissingBackpressureException.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSources that need to be eagerly concatenated

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

Since:

3.0.0

concatEagerDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> concatEagerDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources,
        int maxConcurrency)

Concatenates a Publisher sequence of MaybeSources eagerly into a Flowable sequence, delaying errors until all the inner and the outer sequence terminate and runs a limited number of the inner MaybeSources at once.

Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the emitted source MaybeSources as they are observed. The operator buffers the values emitted by these MaybeSources and then drains them in order, each one after the previous one completes.

Backpressure:

Backpressure is honored towards the downstream and the outer Publisher is expected to support backpressure. Violating this assumption, the operator will signal MissingBackpressureException.

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

sources - a sequence of MaybeSources that need to be eagerly concatenated

maxConcurrency - the maximum number of concurrently running inner MaybeSources; Integer.MAX_VALUE is interpreted as all inner MaybeSources can be active at the same time

Returns:

the new Flowable instance with the specified concatenation behavior

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if maxConcurrency is non-positive

Since:

3.0.0

create

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> create(@NonNull MaybeOnSubscribe<T> onSubscribe)

Provides an API (via a cold Maybe) that bridges the reactive world with the callback-style world.

Example:

 Maybe.<Event>create(emitter -> {
     Callback listener = new Callback() {
         @Override
         public void onEvent(Event e) {
             if (e.isNothing()) {
                 emitter.onComplete();
             } else {
                 emitter.onSuccess(e);
             }
         }

         @Override
         public void onFailure(Exception e) {
             emitter.onError(e);
         }
     };

     AutoCloseable c = api.someMethod(listener);

     emitter.setCancellable(c::close);

 });
 

Whenever a MaybeObserver subscribes to the returned Maybe, the provided MaybeOnSubscribe callback is invoked with a fresh instance of a MaybeEmitter that will interact only with that specific MaybeObserver. If this MaybeObserver disposes the flow (making MaybeEmitter.isDisposed() return true), other observers subscribed to the same returned Maybe are not affected.

Scheduler:

create does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

onSubscribe - the emitter that is called when a MaybeObserver subscribes to the returned Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if onSubscribe is null

See Also:

MaybeOnSubscribe, Cancellable

defer

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> defer(@NonNull Supplier<? extends MaybeSource<? extends T>> supplier)

Calls a Supplier for each individual MaybeObserver to return the actual MaybeSource source to be subscribed to.

Scheduler:

defer does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

supplier - the Supplier that is called for each individual MaybeObserver and returns a MaybeSource instance to subscribe to

Returns:

the new Maybe instance

Throws:

NullPointerException - if supplier is null

empty

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Maybe<T> empty()

Returns a (singleton) Maybe instance that calls onComplete immediately.

Scheduler:

empty does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Returns:

the shared Maybe instance

error

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> error(@NonNull Throwable throwable)

Returns a Maybe that invokes a subscriber's onError method when the subscriber subscribes to it.

Scheduler:

error does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of the item (ostensibly) emitted by the Maybe

Parameters:

throwable - the particular Throwable to pass to onError

Returns:

the new Maybe instance

Throws:

NullPointerException - if throwable is null

See Also:

ReactiveX operators documentation: Throw

error

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> error(@NonNull Supplier<? extends Throwable> supplier)

Returns a Maybe that invokes a MaybeObserver's onError method when the MaybeObserver subscribes to it.

Scheduler:

error does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of the items (ostensibly) emitted by the Maybe

Parameters:

supplier - a Supplier factory to return a Throwable for each individual MaybeObserver

Returns:

the new Maybe instance

Throws:

NullPointerException - if supplier is null

See Also:

ReactiveX operators documentation: Throw

fromAction

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromAction(@NonNull Action action)

Returns a Maybe instance that runs the given Action for each MaybeObserver and emits either its exception or simply completes.

Scheduler:

fromAction does not operate by default on a particular Scheduler.

Error handling:

If the Action throws an exception, the respective Throwable is delivered to the downstream via MaybeObserver.onError(Throwable), except when the downstream has disposed the resulting Maybe source. In this latter case, the Throwable is delivered to the global error handler via RxJavaPlugins.onError(Throwable) as an UndeliverableException.

Type Parameters:

T - the target type

Parameters:

action - the Action to run for each MaybeObserver

Returns:

the new Maybe instance

Throws:

NullPointerException - if action is null

fromCompletable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromCompletable(@NonNull CompletableSource completableSource)

Wraps a CompletableSource into a Maybe.

Scheduler:

fromCompletable does not operate by default on a particular Scheduler.

Type Parameters:

T - the target type

Parameters:

completableSource - the CompletableSource to convert from

Returns:

the new Maybe instance

Throws:

NullPointerException - if completableSource is null

fromSingle

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromSingle(@NonNull SingleSource<T> single)

Wraps a SingleSource into a Maybe.

Scheduler:

fromSingle does not operate by default on a particular Scheduler.

Type Parameters:

T - the target type

Parameters:

single - the SingleSource to convert from

Returns:

the new Maybe instance

Throws:

NullPointerException - if single is null

fromCallable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromCallable(@NonNull Callable<? extends T> callable)

Returns a Maybe that invokes the given Callable for each individual MaybeObserver that subscribes and emits the resulting non-null item via onSuccess while considering a null result from the Callable as indication for valueless completion via onComplete.

This operator allows you to defer the execution of the given Callable until a MaybeObserver subscribes to the returned Maybe. In other terms, this source operator evaluates the given Callable "lazily".

Note that the null handling of this operator differs from the similar source operators in the other base reactive classes. Those operators signal a NullPointerException if the value returned by their Callable is null while this fromCallable considers it to indicate the returned Maybe is empty.

Scheduler:

fromCallable does not operate by default on a particular Scheduler.

Error handling:

Any non-fatal exception thrown by Callable.call() will be forwarded to onError, except if the MaybeObserver disposed the subscription in the meantime. In this latter case, the exception is forwarded to the global error handler via RxJavaPlugins.onError(Throwable) wrapped into a UndeliverableException. Fatal exceptions are rethrown and usually will end up in the executing thread's Thread.UncaughtExceptionHandler.uncaughtException(Thread, Throwable) handler.

Type Parameters:

T - the type of the item emitted by the Maybe.

Parameters:

callable - a Callable instance whose execution should be deferred and performed for each individual MaybeObserver that subscribes to the returned Maybe.

Returns:

the new Maybe instance

Throws:

NullPointerException - if callable is null

See Also:

defer(Supplier), fromSupplier(Supplier)

fromFuture

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromFuture(@NonNull Future<? extends T> future)

Converts a Future into a Maybe, treating a null result as an indication of emptiness.

The operator calls Future.get(), which is a blocking method, on the subscription thread. It is recommended applying subscribeOn(Scheduler) to move this blocking wait to a background thread, and if the Scheduler supports it, interrupt the wait when the flow is disposed.

Unlike 1.x, disposing the Maybe won't cancel the future. If necessary, one can use composition to achieve the cancellation effect: futureMaybe.doOnDispose(() -> future.cancel(true));.

Scheduler:

fromFuture does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of object that the Future returns, and also the type of item to be emitted by the resulting Maybe

Parameters:

future - the source Future

Returns:

the new Maybe instance

Throws:

NullPointerException - if future is null

See Also:

ReactiveX operators documentation: From, fromCompletionStage(CompletionStage)

fromFuture

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromFuture(@NonNull Future<? extends T> future,
        long timeout,
        @NonNull TimeUnit unit)

Converts a Future into a Maybe, with a timeout on the Future.

The operator calls Future.get(long, TimeUnit), which is a blocking method, on the subscription thread. It is recommended applying subscribeOn(Scheduler) to move this blocking wait to a background thread, and if the Scheduler supports it, interrupt the wait when the flow is disposed.

Unlike 1.x, disposing the Maybe won't cancel the future. If necessary, one can use composition to achieve the cancellation effect: futureMaybe.doOnCancel(() -> future.cancel(true));.

Scheduler:

fromFuture does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of object that the Future returns, and also the type of item to be emitted by the resulting Maybe

Parameters:

future - the source Future

timeout - the maximum time to wait before calling get

unit - the TimeUnit of the timeout argument

Returns:

the new Maybe instance

Throws:

NullPointerException - if future or unit is null

See Also:

ReactiveX operators documentation: From, fromCompletionStage(CompletionStage)

fromObservable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromObservable(@NonNull ObservableSource<T> source)

Wraps an ObservableSource into a Maybe and emits the very first item or completes if the source is empty.

Scheduler:

fromObservable does not operate by default on a particular Scheduler.

Type Parameters:

T - the target type

Parameters:

source - the ObservableSource to convert from

Returns:

the new Maybe instance

Throws:

NullPointerException - if source is null

Since:

3.0.0

fromPublisher

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @BackpressureSupport(value=UNBOUNDED_IN)
public static <T> @NonNull Maybe<T> fromPublisher(@NonNull Publisher<T> source)

Wraps a Publisher into a Maybe and emits the very first item or completes if the source is empty.

Backpressure:

The operator consumes the given Publisher in an unbounded manner (requesting Long.MAX_VALUE) but cancels it after one item received.

Scheduler:

fromPublisher does not operate by default on a particular Scheduler.

Type Parameters:

T - the target type

Parameters:

source - the Publisher to convert from

Returns:

the new Maybe instance

Throws:

NullPointerException - if source is null

Since:

3.0.0

fromRunnable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromRunnable(@NonNull Runnable run)

Returns a Maybe instance that runs the given Runnable for each MaybeObserver and emits either its unchecked exception or simply completes.

If the code to be wrapped needs to throw a checked or more broader Throwable exception, that exception has to be converted to an unchecked exception by the wrapped code itself. Alternatively, use the fromAction(Action) method which allows the wrapped code to throw any Throwable exception and will signal it to observers as-is.

Scheduler:

fromRunnable does not operate by default on a particular Scheduler.

Error handling:

If the Runnable throws an exception, the respective Throwable is delivered to the downstream via MaybeObserver.onError(Throwable), except when the downstream has disposed this Maybe source. In this latter case, the Throwable is delivered to the global error handler via RxJavaPlugins.onError(Throwable) as an UndeliverableException.

Type Parameters:

T - the target type

Parameters:

run - the Runnable to run for each MaybeObserver

Returns:

the new Maybe instance

Throws:

NullPointerException - if run is null

See Also:

fromAction(Action)

fromSupplier

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> fromSupplier(@NonNull Supplier<? extends T> supplier)

Returns a Maybe that invokes the given Supplier for each individual MaybeObserver that subscribes and emits the resulting non-null item via onSuccess while considering a null result from the Supplier as indication for valueless completion via onComplete.

This operator allows you to defer the execution of the given Supplier until a MaybeObserver subscribes to the returned Maybe. In other terms, this source operator evaluates the given Supplier "lazily".

Note that the null handling of this operator differs from the similar source operators in the other base reactive classes. Those operators signal a NullPointerException if the value returned by their Supplier is null while this fromSupplier considers it to indicate the returned Maybe is empty.

Scheduler:

fromSupplier does not operate by default on a particular Scheduler.

Error handling:

Any non-fatal exception thrown by Supplier.get() will be forwarded to onError, except if the MaybeObserver disposed the subscription in the meantime. In this latter case, the exception is forwarded to the global error handler via RxJavaPlugins.onError(Throwable) wrapped into a UndeliverableException. Fatal exceptions are rethrown and usually will end up in the executing thread's Thread.UncaughtExceptionHandler.uncaughtException(Thread, Throwable) handler.

Type Parameters:

T - the type of the item emitted by the Maybe.

Parameters:

supplier - a Supplier instance whose execution should be deferred and performed for each individual MaybeObserver that subscribes to the returned Maybe.

Returns:

the new Maybe instance

Throws:

NullPointerException - if supplier is null

Since:

3.0.0

See Also:

defer(Supplier), fromCallable(Callable)

just

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> just(T item)

Returns a Maybe that emits a specified item.

To convert any object into a Maybe that emits that object, pass that object into the just method.

Scheduler:

just does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of that item

Parameters:

item - the item to emit

Returns:

the new Maybe instance

Throws:

NullPointerException - if item is null

See Also:

ReactiveX operators documentation: Just

merge

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> merge(@NonNull Iterable<? extends MaybeSource<? extends T>> sources)

Merges an Iterable sequence of MaybeSource instances into a single Flowable sequence, running all MaybeSources at once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

merge does not operate by default on a particular Scheduler.

Error handling:

If any of the source MaybeSources signal a Throwable via onError, the resulting Flowable terminates with that Throwable and all other source MaybeSources are disposed. If more than one MaybeSource signals an error, the resulting Flowable may terminate with the first one's error or, depending on the concurrency of the sources, may terminate with a CompositeException containing two or more of the various error signals. Throwables that didn't make into the composite will be sent (individually) to the global error handler via RxJavaPlugins.onError(Throwable) method as UndeliverableException errors. Similarly, Throwables signaled by source(s) after the returned Flowable has been cancelled or terminated with a (composite) error will be sent to the same global error handler. Use mergeDelayError(Iterable) to merge sources and terminate only when all source MaybeSources have completed or failed with an error.

Type Parameters:

T - the common and resulting value type

Parameters:

sources - the Iterable sequence of MaybeSource sources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

See Also:

mergeDelayError(Iterable)

merge

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> merge(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Merges a Publisher sequence of MaybeSource instances into a single Flowable sequence, running all MaybeSources at once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

merge does not operate by default on a particular Scheduler.

Error handling:

If any of the source MaybeSources signal a Throwable via onError, the resulting Flowable terminates with that Throwable and all other source MaybeSources are disposed. If more than one MaybeSource signals an error, the resulting Flowable may terminate with the first one's error or, depending on the concurrency of the sources, may terminate with a CompositeException containing two or more of the various error signals. Throwables that didn't make into the composite will be sent (individually) to the global error handler via RxJavaPlugins.onError(Throwable) method as UndeliverableException errors. Similarly, Throwables signaled by source(s) after the returned Flowable has been cancelled or terminated with a (composite) error will be sent to the same global error handler. Use mergeDelayError(Publisher) to merge sources and terminate only when all source MaybeSources have completed or failed with an error.

Type Parameters:

T - the common and resulting value type

Parameters:

sources - the Flowable sequence of MaybeSource sources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

See Also:

mergeDelayError(Publisher)

merge

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> merge(@NonNull Publisher<? extends MaybeSource<? extends T>> sources,
        int maxConcurrency)

Merges a Publisher sequence of MaybeSource instances into a single Flowable sequence, running at most maxConcurrency MaybeSources at once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

merge does not operate by default on a particular Scheduler.

Error handling:

If any of the source MaybeSources signal a Throwable via onError, the resulting Flowable terminates with that Throwable and all other source MaybeSources are disposed. If more than one MaybeSource signals an error, the resulting Flowable may terminate with the first one's error or, depending on the concurrency of the sources, may terminate with a CompositeException containing two or more of the various error signals. Throwables that didn't make into the composite will be sent (individually) to the global error handler via RxJavaPlugins.onError(Throwable) method as UndeliverableException errors. Similarly, Throwables signaled by source(s) after the returned Flowable has been cancelled or terminated with a (composite) error will be sent to the same global error handler. Use mergeDelayError(Publisher, int) to merge sources and terminate only when all source MaybeSources have completed or failed with an error.

Type Parameters:

T - the common and resulting value type

Parameters:

sources - the Flowable sequence of MaybeSource sources

maxConcurrency - the maximum number of concurrently running MaybeSources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if maxConcurrency is non-positive

See Also:

mergeDelayError(Publisher, int)

merge

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> merge(@NonNull MaybeSource<? extends MaybeSource<? extends T>> source)

Flattens a MaybeSource that emits a MaybeSource into a single MaybeSource that emits the item emitted by the nested MaybeSource, without any transformation.

Scheduler:

merge does not operate by default on a particular Scheduler.

Error handling:

The resulting Maybe emits the outer source's or the inner MaybeSource's Throwable as is. Unlike the other merge() operators, this operator won't and can't produce a CompositeException because there is only one possibility for the outer or the inner MaybeSource to emit an onError signal. Therefore, there is no need for a mergeDelayError(MaybeSource<MaybeSource<T>>) operator.

Type Parameters:

T - the value type of the sources and the output

Parameters:

source - a MaybeSource that emits a MaybeSource

Returns:

the new Maybe instance

Throws:

NullPointerException - if source is null

See Also:

ReactiveX operators documentation: Merge

merge

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> merge(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2)

Flattens two MaybeSources into a single Flowable, without any transformation.

You can combine items emitted by multiple MaybeSources so that they appear as a single Flowable, by using the merge method.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

merge does not operate by default on a particular Scheduler.

Error handling:

If any of the source MaybeSources signal a Throwable via onError, the resulting Flowable terminates with that Throwable and all other source MaybeSources are disposed. If more than one MaybeSource signals an error, the resulting Flowable may terminate with the first one's error or, depending on the concurrency of the sources, may terminate with a CompositeException containing two or more of the various error signals. Throwables that didn't make into the composite will be sent (individually) to the global error handler via RxJavaPlugins.onError(Throwable) method as UndeliverableException errors. Similarly, Throwables signaled by source(s) after the returned Flowable has been cancelled or terminated with a (composite) error will be sent to the same global error handler. Use mergeDelayError(MaybeSource, MaybeSource) to merge sources and terminate only when all source MaybeSources have completed or failed with an error.

Type Parameters:

T - the common value type

Parameters:

source1 - a MaybeSource to be merged

source2 - a MaybeSource to be merged

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1 or source2 is null

See Also:

ReactiveX operators documentation: Merge, mergeDelayError(MaybeSource, MaybeSource)

merge

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> merge(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2,
        @NonNull MaybeSource<? extends T> source3)

Flattens three MaybeSources into a single Flowable, without any transformation.

You can combine items emitted by multiple MaybeSources so that they appear as a single Flowable, by using the merge method.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

merge does not operate by default on a particular Scheduler.

Error handling:

If any of the source MaybeSources signal a Throwable via onError, the resulting Flowable terminates with that Throwable and all other source MaybeSources are disposed. If more than one MaybeSource signals an error, the resulting Flowable may terminate with the first one's error or, depending on the concurrency of the sources, may terminate with a CompositeException containing two or more of the various error signals. Throwables that didn't make into the composite will be sent (individually) to the global error handler via RxJavaPlugins.onError(Throwable) method as UndeliverableException errors. Similarly, Throwables signaled by source(s) after the returned Flowable has been cancelled or terminated with a (composite) error will be sent to the same global error handler. Use mergeDelayError(MaybeSource, MaybeSource, MaybeSource) to merge sources and terminate only when all source MaybeSources have completed or failed with an error.

Type Parameters:

T - the common value type

Parameters:

source1 - a MaybeSource to be merged

source2 - a MaybeSource to be merged

source3 - a MaybeSource to be merged

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1, source2 or source3 is null

See Also:

ReactiveX operators documentation: Merge, mergeDelayError(MaybeSource, MaybeSource, MaybeSource)

merge

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> merge(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2,
        @NonNull MaybeSource<? extends T> source3,
        @NonNull MaybeSource<? extends T> source4)

Flattens four MaybeSources into a single Flowable, without any transformation.

You can combine items emitted by multiple MaybeSources so that they appear as a single Flowable, by using the merge method.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

merge does not operate by default on a particular Scheduler.

Error handling:

If any of the source MaybeSources signal a Throwable via onError, the resulting Flowable terminates with that Throwable and all other source MaybeSources are disposed. If more than one MaybeSource signals an error, the resulting Flowable may terminate with the first one's error or, depending on the concurrency of the sources, may terminate with a CompositeException containing two or more of the various error signals. Throwables that didn't make into the composite will be sent (individually) to the global error handler via RxJavaPlugins.onError(Throwable) method as UndeliverableException errors. Similarly, Throwables signaled by source(s) after the returned Flowable has been cancelled or terminated with a (composite) error will be sent to the same global error handler. Use mergeDelayError(MaybeSource, MaybeSource, MaybeSource, MaybeSource) to merge sources and terminate only when all source MaybeSources have completed or failed with an error.

Type Parameters:

T - the common value type

Parameters:

source1 - a MaybeSource to be merged

source2 - a MaybeSource to be merged

source3 - a MaybeSource to be merged

source4 - a MaybeSource to be merged

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1, source2, source3 or source4 is null

See Also:

ReactiveX operators documentation: Merge, mergeDelayError(MaybeSource, MaybeSource, MaybeSource, MaybeSource)

mergeArray

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @SafeVarargs
public static <T> @NonNull Flowable<T> mergeArray(MaybeSource<? extends T>... sources)

Merges an array of MaybeSource instances into a single Flowable sequence, running all MaybeSources at once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

mergeArray does not operate by default on a particular Scheduler.

Error handling:

If any of the source MaybeSources signal a Throwable via onError, the resulting Flowable terminates with that Throwable and all other source MaybeSources are disposed. If more than one MaybeSource signals an error, the resulting Flowable may terminate with the first one's error or, depending on the concurrency of the sources, may terminate with a CompositeException containing two or more of the various error signals. Throwables that didn't make into the composite will be sent (individually) to the global error handler via RxJavaPlugins.onError(Throwable) method as UndeliverableException errors. Similarly, Throwables signaled by source(s) after the returned Flowable has been cancelled or terminated with a (composite) error will be sent to the same global error handler. Use mergeArrayDelayError(MaybeSource...) to merge sources and terminate only when all source MaybeSources have completed or failed with an error.

Type Parameters:

T - the common and resulting value type

Parameters:

sources - the array sequence of MaybeSource sources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

See Also:

mergeArrayDelayError(MaybeSource...)

mergeArrayDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @SafeVarargs
 @NonNull
public static <T> @NonNull Flowable<T> mergeArrayDelayError(@NonNull MaybeSource<? extends T>... sources)

Flattens an array of MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from each of the source MaybeSources without being interrupted by an error notification from one of them.

This behaves like merge(Publisher) except that if any of the merged MaybeSources notify of an error via onError, mergeArrayDelayError will refrain from propagating that error notification until all of the merged MaybeSources have finished emitting items.

Even if multiple merged MaybeSources send onError notifications, mergeArrayDelayError will only invoke the onError method of its subscribers once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

mergeArrayDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

sources - the array of MaybeSources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

See Also:

ReactiveX operators documentation: Merge

mergeDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> mergeDelayError(@NonNull Iterable<? extends MaybeSource<? extends T>> sources)

Flattens an Iterable sequence of MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from each of the source MaybeSources without being interrupted by an error notification from one of them.

This behaves like merge(Publisher) except that if any of the merged MaybeSources notify of an error via onError, mergeDelayError will refrain from propagating that error notification until all of the merged MaybeSources have finished emitting items.

Even if multiple merged MaybeSources send onError notifications, mergeDelayError will only invoke the onError method of its subscribers once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

mergeDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

sources - the Iterable of MaybeSources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

See Also:

ReactiveX operators documentation: Merge

mergeDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Flowable<T> mergeDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Flattens a Publisher that emits MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them or even the main Publisher.

This behaves like merge(Publisher) except that if any of the merged MaybeSources notify of an error via onError, mergeDelayError will refrain from propagating that error notification until all of the merged MaybeSources and the main Publisher have finished emitting items.

Even if multiple merged MaybeSources send onError notifications, mergeDelayError will only invoke the onError method of its subscribers once.

Backpressure:

The operator honors backpressure from downstream. The outer Publisher is consumed in unbounded mode (i.e., no backpressure is applied to it).

Scheduler:

mergeDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

sources - a Publisher that emits MaybeSources

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

See Also:

ReactiveX operators documentation: Merge

mergeDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> mergeDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources,
        int maxConcurrency)

Flattens a Publisher that emits MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them or even the main Publisher as well as limiting the total number of active MaybeSources.

This behaves like merge(Publisher, int) except that if any of the merged MaybeSources notify of an error via onError, mergeDelayError will refrain from propagating that error notification until all of the merged MaybeSources and the main Publisher have finished emitting items.

Even if multiple merged MaybeSources send onError notifications, mergeDelayError will only invoke the onError method of its subscribers once.

Backpressure:

The operator honors backpressure from downstream. The outer Publisher is consumed in unbounded mode (i.e., no backpressure is applied to it).

Scheduler:

mergeDelayError does not operate by default on a particular Scheduler.

History: 2.1.9 - experimental

Type Parameters:

T - the common element base type

Parameters:

sources - a Publisher that emits MaybeSources

maxConcurrency - the maximum number of active inner MaybeSources to be merged at a time

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

IllegalArgumentException - if maxConcurrency is non-positive

Since:

2.2

See Also:

ReactiveX operators documentation: Merge

mergeDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> mergeDelayError(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2)

Flattens two MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from each of the source MaybeSources without being interrupted by an error notification from one of them.

This behaves like merge(MaybeSource, MaybeSource) except that if any of the merged MaybeSources notify of an error via onError, mergeDelayError will refrain from propagating that error notification until all of the merged MaybeSources have finished emitting items.

Even if both merged MaybeSources send onError notifications, mergeDelayError will only invoke the onError method of its subscribers once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

mergeDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

source1 - a MaybeSource to be merged

source2 - a MaybeSource to be merged

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1 or source2 is null

See Also:

ReactiveX operators documentation: Merge

mergeDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> mergeDelayError(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2,
        @NonNull MaybeSource<? extends T> source3)

Flattens three MaybeSource into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them.

This behaves like merge(MaybeSource, MaybeSource, MaybeSource) except that if any of the merged MaybeSources notify of an error via onError, mergeDelayError will refrain from propagating that error notification until all of the merged MaybeSources have finished emitting items.

Even if multiple merged MaybeSources send onError notifications, mergeDelayError will only invoke the onError method of its subscribers once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

mergeDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

source1 - a MaybeSource to be merged

source2 - a MaybeSource to be merged

source3 - a MaybeSource to be merged

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1, source2 or source3 is null

See Also:

ReactiveX operators documentation: Merge

mergeDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> mergeDelayError(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2,
        @NonNull MaybeSource<? extends T> source3,
        @NonNull MaybeSource<? extends T> source4)

Flattens four MaybeSources into one Flowable, in a way that allows a subscriber to receive all successfully emitted items from all of the source MaybeSources without being interrupted by an error notification from one of them.

This behaves like merge(MaybeSource, MaybeSource, MaybeSource, MaybeSource) except that if any of the merged MaybeSources notify of an error via onError, mergeDelayError will refrain from propagating that error notification until all of the merged MaybeSources have finished emitting items.

Even if multiple merged MaybeSources send onError notifications, mergeDelayError will only invoke the onError method of its subscribers once.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

mergeDelayError does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element base type

Parameters:

source1 - a MaybeSource to be merged

source2 - a MaybeSource to be merged

source3 - a MaybeSource to be merged

source4 - a MaybeSource to be merged

Returns:

the new Flowable instance

Throws:

NullPointerException - if source1, source2, source3 or source4 is null

See Also:

ReactiveX operators documentation: Merge

never

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Maybe<T> never()

Returns a Maybe that never sends any items or notifications to a MaybeObserver.

This Maybe is useful primarily for testing purposes.

Scheduler:

never does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of items (not) emitted by the Maybe

Returns:

the shared Maybe instance

See Also:

ReactiveX operators documentation: Never

sequenceEqual

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Single<Boolean> sequenceEqual(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2)

Returns a Single that emits a Boolean value that indicates whether two MaybeSource sequences are the same by comparing the items emitted by each MaybeSource pairwise.

Scheduler:

sequenceEqual does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of items emitted by each MaybeSource

Parameters:

source1 - the first MaybeSource to compare

source2 - the second MaybeSource to compare

Returns:

the new Single instance

Throws:

NullPointerException - if source1 or source2 is null

See Also:

ReactiveX operators documentation: SequenceEqual

sequenceEqual

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Single<Boolean> sequenceEqual(@NonNull MaybeSource<? extends T> source1,
        @NonNull MaybeSource<? extends T> source2,
        @NonNull BiPredicate<? super T,? super T> isEqual)

Returns a Single that emits a Boolean value that indicates whether two MaybeSources are the same by comparing the items emitted by each MaybeSource pairwise based on the results of a specified equality function.

Scheduler:

sequenceEqual does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of items emitted by each MaybeSource

Parameters:

source1 - the first MaybeSource to compare

source2 - the second MaybeSource to compare

isEqual - a function used to compare items emitted by each MaybeSource

Returns:

the new Single instance

Throws:

NullPointerException - if source1, source2 or isEqual is null

See Also:

ReactiveX operators documentation: SequenceEqual

switchOnNext

@BackpressureSupport(value=UNBOUNDED_IN)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> switchOnNext(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Switches between MaybeSources emitted by the source Publisher whenever a new MaybeSource is emitted, disposing the previously running MaybeSource, exposing the success items as a Flowable sequence.

Backpressure:

The sources Publisher is consumed in an unbounded manner (requesting Long.MAX_VALUE). The returned Flowable respects the backpressure from the downstream.

Scheduler:

switchOnNext does not operate by default on a particular Scheduler.

Error handling:

The returned sequence fails with the first error signaled by the sources Publisher or the currently running MaybeSource, disposing the rest. Late errors are forwarded to the global error handler via RxJavaPlugins.onError(Throwable).

Type Parameters:

T - the element type of the MaybeSources

Parameters:

sources - the Publisher sequence of inner MaybeSources to switch between

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

Since:

3.0.0

See Also:

switchOnNextDelayError(Publisher), ReactiveX operators documentation: Switch

switchOnNextDelayError

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Flowable<T> switchOnNextDelayError(@NonNull Publisher<? extends MaybeSource<? extends T>> sources)

Switches between MaybeSources emitted by the source Publisher whenever a new MaybeSource is emitted, disposing the previously running MaybeSource, exposing the success items as a Flowable sequence and delaying all errors from all of them until all terminate.

Backpressure:

The sources Publisher is consumed in an unbounded manner (requesting Long.MAX_VALUE). The returned Flowable respects the backpressure from the downstream.

Scheduler:

switchOnNextDelayError does not operate by default on a particular Scheduler.

Error handling:

The returned Flowable collects all errors emitted by either the sources Publisher or any inner MaybeSource and emits them as a CompositeException when all sources terminate. If only one source ever failed, its error is emitted as-is at the end.

Type Parameters:

T - the element type of the MaybeSources

Parameters:

sources - the Publisher sequence of inner MaybeSources to switch between

Returns:

the new Flowable instance

Throws:

NullPointerException - if sources is null

Since:

3.0.0

See Also:

switchOnNext(Publisher), ReactiveX operators documentation: Switch

timer

@CheckReturnValue
 @SchedulerSupport(value="io.reactivex:computation")
 @NonNull
public static @NonNull Maybe<Long> timer(long delay,
        @NonNull TimeUnit unit)

Returns a Maybe that emits 0L after a specified delay.

Scheduler:

timer operates by default on the computation Scheduler.

Parameters:

delay - the initial delay before emitting a single 0L

unit - time units to use for delay

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit is null

See Also:

ReactiveX operators documentation: Timer

timer

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public static @NonNull Maybe<Long> timer(long delay,
        @NonNull TimeUnit unit,
        @NonNull Scheduler scheduler)

Returns a Maybe that emits 0L after a specified delay on a specified Scheduler.

Scheduler:

You specify which Scheduler this operator will use.

Parameters:

delay - the initial delay before emitting a single 0L

unit - time units to use for delay

scheduler - the Scheduler to use for scheduling the item

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or scheduler is null

See Also:

ReactiveX operators documentation: Timer

unsafeCreate

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> unsafeCreate(@NonNull MaybeSource<T> onSubscribe)

Advanced use only: creates a Maybe instance without any safeguards by using a callback that is called with a MaybeObserver.

Scheduler:

unsafeCreate does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

onSubscribe - the function that is called with the subscribing MaybeObserver

Returns:

the new Maybe instance

Throws:

IllegalArgumentException - if onSubscribe is a Maybe

NullPointerException - if onSubscribe is null

using

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T,D> @NonNull Maybe<T> using(@NonNull Supplier<? extends D> resourceSupplier,
        @NonNull Function<? super D,? extends MaybeSource<? extends T>> sourceSupplier,
        @NonNull Consumer<? super D> resourceCleanup)

Constructs a Maybe that creates a dependent resource object which is disposed of when the generated MaybeSource terminates or the downstream calls dispose().

Scheduler:

using does not operate by default on a particular Scheduler.

Type Parameters:

T - the element type of the generated MaybeSource

D - the type of the resource associated with the output sequence

Parameters:

resourceSupplier - the factory function to create a resource object that depends on the Maybe

sourceSupplier - the factory function to create a MaybeSource

resourceCleanup - the function that will dispose of the resource

Returns:

the new Maybe instance

Throws:

NullPointerException - if resourceSupplier, sourceSupplier or resourceCleanup is null

See Also:

ReactiveX operators documentation: Using

using

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T,D> @NonNull Maybe<T> using(@NonNull Supplier<? extends D> resourceSupplier,
        @NonNull Function<? super D,? extends MaybeSource<? extends T>> sourceSupplier,
        @NonNull Consumer<? super D> resourceCleanup,
        boolean eager)

Constructs a Maybe that creates a dependent resource object which is disposed first ({code eager == true}) when the generated MaybeSource terminates or the downstream disposes; or after ({code eager == false}).

Eager disposal is particularly appropriate for a synchronous Maybe that reuses resources. disposeAction will only be called once per subscription.

Scheduler:

using does not operate by default on a particular Scheduler.

Type Parameters:

T - the element type of the generated MaybeSource

D - the type of the resource associated with the output sequence

Parameters:

resourceSupplier - the factory function to create a resource object that depends on the Maybe

sourceSupplier - the factory function to create a MaybeSource

resourceCleanup - the function that will dispose of the resource

eager - If true then resource disposal will happen either on a dispose() call before the upstream is disposed or just before the emission of a terminal event (onSuccess, onComplete or onError). If false the resource disposal will happen either on a dispose() call after the upstream is disposed or just after the emission of a terminal event (onSuccess, onComplete or onError).

Returns:

the new Maybe instance

Throws:

NullPointerException - if resourceSupplier, sourceSupplier or resourceCleanup is null

See Also:

ReactiveX operators documentation: Using

wrap

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T> @NonNull Maybe<T> wrap(@NonNull MaybeSource<T> source)

Wraps a MaybeSource instance into a new Maybe instance if not already a Maybe instance.

Scheduler:

wrap does not operate by default on a particular Scheduler.

Type Parameters:

T - the value type

Parameters:

source - the source to wrap

Returns:

the new wrapped or cast Maybe instance

Throws:

NullPointerException - if source is null

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T,R> @NonNull Maybe<R> zip(@NonNull Iterable<? extends MaybeSource<? extends T>> sources,
        @NonNull Function<? super Object[],? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of items emitted, in sequence, by an Iterable of other MaybeSources.

Note on method signature: since Java doesn't allow creating a generic array with new T[], the implementation of this operator has to create an Object[] instead. Unfortunately, a Function<Integer[], R> passed to the method would trigger a ClassCastException.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T - the common value type

R - the zipped result type

Parameters:

sources - an Iterable of source MaybeSources

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if zipper or sources is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull BiFunction<? super T1,? super T2,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of two items emitted, in sequence, by two other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,T3,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull MaybeSource<? extends T3> source3,
        @NonNull Function3<? super T1,? super T2,? super T3,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of three items emitted, in sequence, by three other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

T3 - the value type of the third source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

source3 - a third source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2, source3 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,T3,T4,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull MaybeSource<? extends T3> source3,
        @NonNull MaybeSource<? extends T4> source4,
        @NonNull Function4<? super T1,? super T2,? super T3,? super T4,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of four items emitted, in sequence, by four other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

T3 - the value type of the third source

T4 - the value type of the fourth source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

source3 - a third source MaybeSource

source4 - a fourth source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2, source3, source4 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,T3,T4,T5,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull MaybeSource<? extends T3> source3,
        @NonNull MaybeSource<? extends T4> source4,
        @NonNull MaybeSource<? extends T5> source5,
        @NonNull Function5<? super T1,? super T2,? super T3,? super T4,? super T5,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of five items emitted, in sequence, by five other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

T3 - the value type of the third source

T4 - the value type of the fourth source

T5 - the value type of the fifth source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

source3 - a third source MaybeSource

source4 - a fourth source MaybeSource

source5 - a fifth source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2, source3, source4, source5 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,T3,T4,T5,T6,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull MaybeSource<? extends T3> source3,
        @NonNull MaybeSource<? extends T4> source4,
        @NonNull MaybeSource<? extends T5> source5,
        @NonNull MaybeSource<? extends T6> source6,
        @NonNull Function6<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of six items emitted, in sequence, by six other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

T3 - the value type of the third source

T4 - the value type of the fourth source

T5 - the value type of the fifth source

T6 - the value type of the sixth source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

source3 - a third source MaybeSource

source4 - a fourth source MaybeSource

source5 - a fifth source MaybeSource

source6 - a sixth source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2, source3, source4, source5, source6 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,T3,T4,T5,T6,T7,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull MaybeSource<? extends T3> source3,
        @NonNull MaybeSource<? extends T4> source4,
        @NonNull MaybeSource<? extends T5> source5,
        @NonNull MaybeSource<? extends T6> source6,
        @NonNull MaybeSource<? extends T7> source7,
        @NonNull Function7<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? super T7,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of seven items emitted, in sequence, by seven other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

T3 - the value type of the third source

T4 - the value type of the fourth source

T5 - the value type of the fifth source

T6 - the value type of the sixth source

T7 - the value type of the seventh source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

source3 - a third source MaybeSource

source4 - a fourth source MaybeSource

source5 - a fifth source MaybeSource

source6 - a sixth source MaybeSource

source7 - a seventh source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2, source3, source4, source5, source6, source7 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,T3,T4,T5,T6,T7,T8,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull MaybeSource<? extends T3> source3,
        @NonNull MaybeSource<? extends T4> source4,
        @NonNull MaybeSource<? extends T5> source5,
        @NonNull MaybeSource<? extends T6> source6,
        @NonNull MaybeSource<? extends T7> source7,
        @NonNull MaybeSource<? extends T8> source8,
        @NonNull Function8<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? super T7,? super T8,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of eight items emitted, in sequence, by eight other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

T3 - the value type of the third source

T4 - the value type of the fourth source

T5 - the value type of the fifth source

T6 - the value type of the sixth source

T7 - the value type of the seventh source

T8 - the value type of the eighth source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

source3 - a third source MaybeSource

source4 - a fourth source MaybeSource

source5 - a fifth source MaybeSource

source6 - a sixth source MaybeSource

source7 - a seventh source MaybeSource

source8 - an eighth source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2, source3, source4, source5, source6, source7, source8 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zip

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public static <T1,T2,T3,T4,T5,T6,T7,T8,T9,R> @NonNull Maybe<R> zip(@NonNull MaybeSource<? extends T1> source1,
        @NonNull MaybeSource<? extends T2> source2,
        @NonNull MaybeSource<? extends T3> source3,
        @NonNull MaybeSource<? extends T4> source4,
        @NonNull MaybeSource<? extends T5> source5,
        @NonNull MaybeSource<? extends T6> source6,
        @NonNull MaybeSource<? extends T7> source7,
        @NonNull MaybeSource<? extends T8> source8,
        @NonNull MaybeSource<? extends T9> source9,
        @NonNull Function9<? super T1,? super T2,? super T3,? super T4,? super T5,? super T6,? super T7,? super T8,? super T9,? extends R> zipper)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of nine items emitted, in sequence, by nine other MaybeSources.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zip does not operate by default on a particular Scheduler.

Type Parameters:

T1 - the value type of the first source

T2 - the value type of the second source

T3 - the value type of the third source

T4 - the value type of the fourth source

T5 - the value type of the fifth source

T6 - the value type of the sixth source

T7 - the value type of the seventh source

T8 - the value type of the eighth source

T9 - the value type of the ninth source

R - the zipped result type

Parameters:

source1 - the first source MaybeSource

source2 - a second source MaybeSource

source3 - a third source MaybeSource

source4 - a fourth source MaybeSource

source5 - a fifth source MaybeSource

source6 - a sixth source MaybeSource

source7 - a seventh source MaybeSource

source8 - an eighth source MaybeSource

source9 - a ninth source MaybeSource

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if source1, source2, source3, source4, source5, source6, source7, source8, source9 or zipper is null

See Also:

ReactiveX operators documentation: Zip

zipArray

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @SafeVarargs
public static <T,R> @NonNull Maybe<R> zipArray(@NonNull Function<? super Object[],? extends R> zipper,
        @NonNull MaybeSource<? extends T>... sources)

Returns a Maybe that emits the results of a specified combiner function applied to combinations of items emitted, in sequence, by an array of other MaybeSources.

Note on method signature: since Java doesn't allow creating a generic array with new T[], the implementation of this operator has to create an Object[] instead. Unfortunately, a Function<Integer[], R> passed to the method would trigger a ClassCastException.

This operator terminates eagerly if any of the source MaybeSources signal an onError or onComplete. This also means it is possible some sources may not get subscribed to at all.

Scheduler:

zipArray does not operate by default on a particular Scheduler.

Type Parameters:

T - the common element type

R - the result type

Parameters:

sources - an array of source MaybeSources

zipper - a function that, when applied to an item emitted by each of the source MaybeSources, results in an item that will be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if sources or zipper is null

See Also:

ReactiveX operators documentation: Zip

ambWith

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> ambWith(@NonNull MaybeSource<? extends T> other)

Mirrors the MaybeSource (current or provided) that first signals an event.

Scheduler:

ambWith does not operate by default on a particular Scheduler.

Parameters:

other - a MaybeSource competing to react first. A subscription to this provided source will occur after subscribing to the current source.

Returns:

the new Maybe instance

Throws:

NullPointerException - if other is null

See Also:

ReactiveX operators documentation: Amb

blockingGet

@CheckReturnValue
 @SchedulerSupport(value="none")
 @Nullable
public final T blockingGet()

Waits in a blocking fashion until the current Maybe signals a success value (which is returned), null if completed or an exception (which is propagated).

Scheduler:

blockingGet does not operate by default on a particular Scheduler.

Error handling:

If the source signals an error, the operator wraps a checked Exception into RuntimeException and throws that. Otherwise, RuntimeExceptions and Errors are rethrown as they are.

Returns:

the success value

blockingGet

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final T blockingGet(@NonNull T defaultValue)

Waits in a blocking fashion until the current Maybe signals a success value (which is returned), defaultValue if completed or an exception (which is propagated).

Scheduler:

blockingGet does not operate by default on a particular Scheduler.

Error handling:

If the source signals an error, the operator wraps a checked Exception into RuntimeException and throws that. Otherwise, RuntimeExceptions and Errors are rethrown as they are.

Parameters:

defaultValue - the default item to return if this Maybe is empty

Returns:

the success value

Throws:

NullPointerException - if defaultValue is null

blockingSubscribe

@SchedulerSupport(value="none")
public final void blockingSubscribe()

Subscribes to the current Maybe and blocks the current thread until it terminates.

Scheduler:

blockingSubscribe does not operate by default on a particular Scheduler.

Error handling:

If the current Maybe signals an error, the Throwable is routed to the global error handler via RxJavaPlugins.onError(Throwable). If the current thread is interrupted, an InterruptedException is routed to the same global error handler.

Since:

3.0.0

See Also:

blockingSubscribe(Consumer), blockingSubscribe(Consumer, Consumer), blockingSubscribe(Consumer, Consumer, Action)

blockingSubscribe

@SchedulerSupport(value="none")
public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess)

Subscribes to the current Maybe and calls given onSuccess callback on the current thread when it completes normally.

Scheduler:

blockingSubscribe does not operate by default on a particular Scheduler.

Error handling:

If either the current Maybe signals an error or onSuccess throws, the respective Throwable is routed to the global error handler via RxJavaPlugins.onError(Throwable). If the current thread is interrupted, an InterruptedException is routed to the same global error handler.

Parameters:

onSuccess - the Consumer to call if the current Maybe succeeds

Throws:

NullPointerException - if onSuccess is null

Since:

3.0.0

See Also:

blockingSubscribe(Consumer, Consumer), blockingSubscribe(Consumer, Consumer, Action)

blockingSubscribe

@SchedulerSupport(value="none")
public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess,
        @NonNull Consumer<? super Throwable> onError)

Subscribes to the current Maybe and calls the appropriate callback on the current thread when it terminates.

Scheduler:

blockingSubscribe does not operate by default on a particular Scheduler.

Error handling:

If either onSuccess or onError throw, the Throwable is routed to the global error handler via RxJavaPlugins.onError(Throwable). If the current thread is interrupted, the onError consumer is called with an InterruptedException.

Parameters:

onSuccess - the Consumer to call if the current Maybe succeeds

onError - the Consumer to call if the current Maybe signals an error

Throws:

NullPointerException - if onSuccess or onError is null

Since:

3.0.0

See Also:

blockingSubscribe(Consumer, Consumer, Action)

blockingSubscribe

@SchedulerSupport(value="none")
public final void blockingSubscribe(@NonNull Consumer<? super T> onSuccess,
        @NonNull Consumer<? super Throwable> onError,
        @NonNull Action onComplete)

Subscribes to the current Maybe and calls the appropriate callback on the current thread when it terminates.

Scheduler:

blockingSubscribe does not operate by default on a particular Scheduler.

Error handling:

If either onSuccess, onError or onComplete throw, the Throwable is routed to the global error handler via RxJavaPlugins.onError(Throwable). If the current thread is interrupted, the onError consumer is called with an InterruptedException.

Parameters:

onSuccess - the Consumer to call if the current Maybe succeeds

onError - the Consumer to call if the current Maybe signals an error

onComplete - the Action to call if the current Maybe completes without a value

Throws:

NullPointerException - if onSuccess, onError or onComplete is null

Since:

3.0.0

blockingSubscribe

@SchedulerSupport(value="none")
public final void blockingSubscribe(@NonNull MaybeObserver<? super T> observer)

Subscribes to the current Maybe and calls the appropriate MaybeObserver method on the current thread.

Scheduler:

blockingSubscribe does not operate by default on a particular Scheduler.

Error handling:

An onError signal is delivered to the MaybeObserver.onError(Throwable) method. If any of the MaybeObserver's methods throw, the RuntimeException is propagated to the caller of this method. If the current thread is interrupted, an InterruptedException is delivered to observer.onError.

Parameters:

observer - the MaybeObserver to call methods on the current thread

Throws:

NullPointerException - if observer is null

Since:

3.0.0

cache

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> cache()

Returns a Maybe that subscribes to this Maybe lazily, caches its event and replays it, to all the downstream subscribers.

The operator subscribes only when the first downstream subscriber subscribes and maintains a single subscription towards this Maybe.

Note: You sacrifice the ability to dispose the origin when you use the cache.

Scheduler:

cache does not operate by default on a particular Scheduler.

Returns:

the new Maybe instance

See Also:

ReactiveX operators documentation: Replay

cast

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<U> cast(@NonNull Class<? extends U> clazz)

Casts the success value of the current Maybe into the target type or signals a ClassCastException if not compatible.

Scheduler:

cast does not operate by default on a particular Scheduler.

Type Parameters:

U - the target type

Parameters:

clazz - the type token to use for casting the success result from the current Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if clazz is null

compose

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final <R> @NonNull Maybe<R> compose(@NonNull MaybeTransformer<? super T,? extends R> transformer)

Transform a Maybe by applying a particular MaybeTransformer function to it.

This method operates on the Maybe itself whereas lift(io.reactivex.rxjava3.core.MaybeOperator<? extends R, ? super T>) operates on the Maybe's MaybeObservers.

If the operator you are creating is designed to act on the individual item emitted by a Maybe, use lift(io.reactivex.rxjava3.core.MaybeOperator<? extends R, ? super T>). If your operator is designed to transform the current Maybe as a whole (for instance, by applying a particular set of existing RxJava operators to it) use compose.

Scheduler:

compose does not operate by default on a particular Scheduler.

Type Parameters:

R - the value type of the Maybe returned by the transformer function

Parameters:

transformer - the transformer function, not null

Returns:

the new Maybe instance

Throws:

NullPointerException - if transformer is null

See Also:

RxJava wiki: Implementing Your Own Operators

concatMap

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> concatMap(@NonNull Function<? super T,? extends MaybeSource<? extends R>> mapper)

Returns a Maybe that is based on applying a specified function to the item emitted by the current Maybe, where that function returns a MaybeSource.

Note that flatMap and concatMap for Maybe is the same operation.

Scheduler:

concatMap does not operate by default on a particular Scheduler.

Type Parameters:

R - the result value type

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns a MaybeSource

Returns:

the new Maybe instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: FlatMap

concatMapCompletable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Completable concatMapCompletable(@NonNull Function<? super T,? extends CompletableSource> mapper)

Returns a Completable that completes based on applying a specified function to the item emitted by the current Maybe, where that function returns a Completable.

This operator is an alias for flatMapCompletable(Function).

Scheduler:

concatMapCompletable does not operate by default on a particular Scheduler.

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns a Completable

Returns:

the new Completable instance

Throws:

NullPointerException - if mapper is null

Since:

3.0.0

See Also:

ReactiveX operators documentation: FlatMap

concatMapSingle

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> concatMapSingle(@NonNull Function<? super T,? extends SingleSource<? extends R>> mapper)

Returns a Maybe based on applying a specified function to the item emitted by the current Maybe, where that function returns a Single. When this Maybe just completes the resulting Maybe completes as well.

This operator is an alias for flatMapSingle(Function).

Scheduler:

concatMapSingle does not operate by default on a particular Scheduler.

Type Parameters:

R - the result value type

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns a Single

Returns:

the new Maybe instance

Throws:

NullPointerException - if mapper is null

Since:

3.0.0

See Also:

ReactiveX operators documentation: FlatMap

concatWith

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Flowable<T> concatWith(@NonNull MaybeSource<? extends T> other)

Returns a Flowable that emits the items emitted from the current Maybe, then the other MaybeSource, one after the other, without interleaving them.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

concatWith does not operate by default on a particular Scheduler.

Parameters:

other - a MaybeSource to be concatenated after the current

Returns:

the new Flowable instance

Throws:

NullPointerException - if other is null

See Also:

ReactiveX operators documentation: Concat

contains

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Single<Boolean> contains(@NonNull Object item)

Returns a Single that emits a Boolean that indicates whether the current Maybe emitted a specified item.

Scheduler:

contains does not operate by default on a particular Scheduler.

Parameters:

item - the item to search for in the emissions from the current Maybe, not null

Returns:

the new Single instance

Throws:

NullPointerException - if item is null

See Also:

ReactiveX operators documentation: Contains

count

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Single<Long> count()

Returns a Single that counts the total number of items emitted (0 or 1) by the current Maybe and emits this count as a 64-bit Long.

Scheduler:

count does not operate by default on a particular Scheduler.

Returns:

the new Single instance

See Also:

ReactiveX operators documentation: Count

defaultIfEmpty

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Single<T> defaultIfEmpty(@NonNull T defaultItem)

Returns a Single that emits the item emitted by the current Maybe or a specified default item if the current Maybe is empty.

Scheduler:

defaultIfEmpty does not operate by default on a particular Scheduler.

Parameters:

defaultItem - the item to emit if the current Maybe emits no items

Returns:

the new Single instance

Throws:

NullPointerException - if defaultItem is null

See Also:

ReactiveX operators documentation: DefaultIfEmpty

dematerialize

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> dematerialize(@NonNull Function<? super T,Notification<R>> selector)

Maps the Notification success value of the current Maybe back into normal onSuccess, onError or onComplete signals.

The intended use of the selector function is to perform a type-safe identity mapping (see example) on a source that is already of type Notification<T>. The Java language doesn't allow limiting instance methods to a certain generic argument shape, therefore, a function is used to ensure the conversion remains type safe.

Regular onError or onComplete signals from the current Maybe are passed along to the downstream.

Scheduler:

dematerialize does not operate by default on a particular Scheduler.

Example:

 Maybe.just(Notification.createOnNext(1))
 .dematerialize(notification -> notification)
 .test()
 .assertResult(1);
 

Type Parameters:

R - the result type

Parameters:

selector - the function called with the success item and should return a Notification instance.

Returns:

the new Maybe instance

Throws:

NullPointerException - if selector is null

Since:

3.0.0

See Also:

materialize()

delay

@CheckReturnValue
 @SchedulerSupport(value="io.reactivex:computation")
 @NonNull
public final @NonNull Maybe<T> delay(long time,
        @NonNull TimeUnit unit)

Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay. An error signal will not be delayed.

Scheduler:

This version of delay operates by default on the computation Scheduler.

Parameters:

time - the delay to shift the source by

unit - the TimeUnit in which time is defined

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit is null

See Also:

ReactiveX operators documentation: Delay, delay(long, TimeUnit, Scheduler, boolean)

delay

@CheckReturnValue
 @SchedulerSupport(value="io.reactivex:computation")
 @NonNull
public final @NonNull Maybe<T> delay(long time,
        @NonNull TimeUnit unit,
        boolean delayError)

Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay.

Scheduler:

This version of delay operates by default on the computation Scheduler.

Parameters:

time - the delay to shift the source by

unit - the TimeUnit in which time is defined

delayError - if true, both success and error signals are delayed. if false, only success signals are delayed.

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit is null

Since:

3.0.0

See Also:

ReactiveX operators documentation: Delay, delay(long, TimeUnit, Scheduler, boolean)

delay

@CheckReturnValue
 @SchedulerSupport(value="custom")
 @NonNull
public final @NonNull Maybe<T> delay(long time,
        @NonNull TimeUnit unit,
        @NonNull Scheduler scheduler)

Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay. An error signal will not be delayed.

Scheduler:

you specify the Scheduler where the non-blocking wait and emission happens

Parameters:

time - the delay to shift the source by

unit - the TimeUnit in which time is defined

scheduler - the Scheduler to use for delaying

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or scheduler is null

See Also:

ReactiveX operators documentation: Delay, delay(long, TimeUnit, Scheduler, boolean)

delay

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<T> delay(long time,
        @NonNull TimeUnit unit,
        @NonNull Scheduler scheduler,
        boolean delayError)

Returns a Maybe that signals the events emitted by the current Maybe shifted forward in time by a specified delay running on the specified Scheduler.

Scheduler:

you specify which Scheduler this operator will use.

Parameters:

time - the delay to shift the source by

unit - the TimeUnit in which time is defined

scheduler - the Scheduler to use for delaying

delayError - if true, both success and error signals are delayed. if false, only success signals are delayed.

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or scheduler is null

Since:

3.0.0

See Also:

ReactiveX operators documentation: Delay

delay

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @BackpressureSupport(value=UNBOUNDED_IN)
public final <U> @NonNull Maybe<T> delay(@NonNull Publisher<U> delayIndicator)

Delays the emission of this Maybe until the given Publisher signals an item or completes.

Backpressure:

The delayIndicator is consumed in an unbounded manner but is cancelled after the first item it produces.

Scheduler:

This version of delay does not operate by default on a particular Scheduler.

Type Parameters:

U - the subscription delay value type (ignored)

Parameters:

delayIndicator - the Publisher that gets subscribed to when this Maybe signals an event and that signal is emitted when the Publisher signals an item or completes

Returns:

the new Maybe instance

Throws:

NullPointerException - if delayIndicator is null

See Also:

ReactiveX operators documentation: Delay

delaySubscription

@BackpressureSupport(value=UNBOUNDED_IN)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<T> delaySubscription(@NonNull Publisher<U> subscriptionIndicator)

Returns a Maybe that delays the subscription to this Maybe until the other Publisher emits an element or completes normally.

Backpressure:

The Publisher source is consumed in an unbounded fashion (without applying backpressure).

Scheduler:

This method does not operate by default on a particular Scheduler.

Type Parameters:

U - the value type of the other Publisher, irrelevant

Parameters:

subscriptionIndicator - the other Publisher that should trigger the subscription to this Publisher.

Returns:

the new Maybe instance

Throws:

NullPointerException - if subscriptionIndicator is null

delaySubscription

@CheckReturnValue
 @SchedulerSupport(value="io.reactivex:computation")
 @NonNull
public final @NonNull Maybe<T> delaySubscription(long time,
        @NonNull TimeUnit unit)

Returns a Maybe that delays the subscription to the current Maybe by a given amount of time.

Scheduler:

This version of delaySubscription operates by default on the computation Scheduler.

Parameters:

time - the time to delay the subscription

unit - the time unit of delay

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit is null

See Also:

ReactiveX operators documentation: Delay, delaySubscription(long, TimeUnit, Scheduler)

delaySubscription

@CheckReturnValue
 @SchedulerSupport(value="custom")
 @NonNull
public final @NonNull Maybe<T> delaySubscription(long time,
        @NonNull TimeUnit unit,
        @NonNull Scheduler scheduler)

Returns a Maybe that delays the subscription to the current Maybe by a given amount of time, both waiting and subscribing on a given Scheduler.

Scheduler:

You specify which Scheduler this operator will use.

Parameters:

time - the time to delay the subscription

unit - the time unit of delay

scheduler - the Scheduler on which the waiting and subscription will happen

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or scheduler is null

See Also:

ReactiveX operators documentation: Delay

doAfterSuccess

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doAfterSuccess(@NonNull Consumer<? super T> onAfterSuccess)

Calls the specified Consumer with the success item after this item has been emitted to the downstream.

Note that the onAfterSuccess action is shared between subscriptions and as such should be thread-safe.

Scheduler:

doAfterSuccess does not operate by default on a particular Scheduler.

History: 2.0.1 - experimental

Parameters:

onAfterSuccess - the Consumer that will be called after emitting an item from upstream to the downstream

Returns:

the new Maybe instance

Throws:

NullPointerException - if onAfterSuccess is null

Since:

2.1

doAfterTerminate

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doAfterTerminate(@NonNull Action onAfterTerminate)

Registers an Action to be called when this Maybe invokes either onSuccess, onComplete or onError.

Scheduler:

doAfterTerminate does not operate by default on a particular Scheduler.

Parameters:

onAfterTerminate - an Action to be invoked when the current Maybe finishes

Returns:

the new Maybe instance

Throws:

NullPointerException - if onAfterTerminate is null

See Also:

ReactiveX operators documentation: Do

doFinally

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doFinally(@NonNull Action onFinally)

Calls the specified action after this Maybe signals onSuccess, onError or onComplete or gets disposed by the downstream.

In case of a race between a terminal event and a dispose call, the provided onFinally action is executed once per subscription.

Note that the onFinally action is shared between subscriptions and as such should be thread-safe.

Scheduler:

doFinally does not operate by default on a particular Scheduler.

History: 2.0.1 - experimental

Parameters:

onFinally - the action called when this Maybe terminates or gets disposed

Returns:

the new Maybe instance

Throws:

NullPointerException - if onFinally is null

Since:

2.1

doOnDispose

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doOnDispose(@NonNull Action onDispose)

Calls the shared Action if a MaybeObserver subscribed to the current Maybe disposes the common Disposable it received via onSubscribe.

Scheduler:

doOnDispose does not operate by default on a particular Scheduler.

Parameters:

onDispose - the action called when the subscription is disposed

Returns:

the new Maybe instance

Throws:

NullPointerException - if onDispose is null

doOnComplete

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doOnComplete(@NonNull Action onComplete)

Invokes an Action just before the current Maybe calls onComplete.

Scheduler:

doOnComplete does not operate by default on a particular Scheduler.

Parameters:

onComplete - the action to invoke when the current Maybe calls onComplete

Returns:

the new Maybe with the side-effecting behavior applied

Throws:

NullPointerException - if onComplete is null

See Also:

ReactiveX operators documentation: Do

doOnError

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doOnError(@NonNull Consumer<? super Throwable> onError)

Calls the shared Consumer with the error sent via onError for each MaybeObserver that subscribes to the current Maybe.

Scheduler:

doOnError does not operate by default on a particular Scheduler.

Parameters:

onError - the consumer called with the success value of onError

Returns:

the new Maybe instance

Throws:

NullPointerException - if onError is null

doOnEvent

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> doOnEvent(@NonNull BiConsumer<? super T,? super Throwable> onEvent)

Calls the given onEvent callback with the (success value, null) for an onSuccess, (null, throwable) for an onError or (null, null) for an onComplete signal from this Maybe before delivering said signal to the downstream.

The exceptions thrown from the callback will override the event so the downstream receives the error instead of the original signal.

Scheduler:

doOnEvent does not operate by default on a particular Scheduler.

Parameters:

onEvent - the callback to call with the success value or the exception, whichever is not null

Returns:

the new Maybe instance

Throws:

NullPointerException - if onEvent is null

doOnLifecycle

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> doOnLifecycle(@NonNull Consumer<? super Disposable> onSubscribe,
        @NonNull Action onDispose)

Calls the appropriate onXXX method (shared between all MaybeObservers) for the lifecycle events of the sequence (subscription, disposal).

Scheduler:

doOnLifecycle does not operate by default on a particular Scheduler.

Parameters:

onSubscribe - a Consumer called with the Disposable sent via MaybeObserver.onSubscribe(Disposable)

onDispose - called when the downstream disposes the Disposable via dispose()

Returns:

the new Maybe instance

Throws:

NullPointerException - if onSubscribe or onDispose is null

Since:

3.0.0

See Also:

ReactiveX operators documentation: Do

doOnSubscribe

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doOnSubscribe(@NonNull Consumer<? super Disposable> onSubscribe)

Calls the shared Consumer with the Disposable sent through the onSubscribe for each MaybeObserver that subscribes to the current Maybe.

Scheduler:

doOnSubscribe does not operate by default on a particular Scheduler.

Parameters:

onSubscribe - the Consumer called with the Disposable sent via onSubscribe

Returns:

the new Maybe instance

Throws:

NullPointerException - if onSubscribe is null

doOnTerminate

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doOnTerminate(@NonNull Action onTerminate)

Returns a Maybe instance that calls the given onTerminate callback just before this Maybe completes normally or with an exception.

This differs from doAfterTerminate in that this happens before the onComplete or onError notification.

Scheduler:

doOnTerminate does not operate by default on a particular Scheduler.

History: 2.2.7 - experimental

Parameters:

onTerminate - the action to invoke when the consumer calls onComplete or onError

Returns:

the new Maybe instance

Throws:

NullPointerException - if onTerminate is null

Since:

3.0.0

See Also:

ReactiveX operators documentation: Do, doOnTerminate(Action)

doOnSuccess

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> doOnSuccess(@NonNull Consumer<? super T> onSuccess)

Calls the shared Consumer with the success value sent via onSuccess for each MaybeObserver that subscribes to the current Maybe.

Scheduler:

doOnSuccess does not operate by default on a particular Scheduler.

Parameters:

onSuccess - the Consumer called with the success value of the upstream

Returns:

the new Maybe instance

Throws:

NullPointerException - if onSuccess is null

filter

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> filter(@NonNull Predicate<? super T> predicate)

Filters the success item of the Maybe via a predicate function and emitting it if the predicate returns true, completing otherwise.

Scheduler:

filter does not operate by default on a particular Scheduler.

Parameters:

predicate - a function that evaluates the item emitted by the current Maybe, returning true if it passes the filter

Returns:

the new Maybe instance

Throws:

NullPointerException - if predicate is null

See Also:

ReactiveX operators documentation: Filter

flatMap

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> flatMap(@NonNull Function<? super T,? extends MaybeSource<? extends R>> mapper)

Returns a Maybe that is based on applying a specified function to the item emitted by the current Maybe, where that function returns a MaybeSource.

Scheduler:

flatMap does not operate by default on a particular Scheduler.

Note that flatMap and concatMap for Maybe is the same operation.

Type Parameters:

R - the result value type

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns a MaybeSource

Returns:

the new Maybe instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: FlatMap

flatMap

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> flatMap(@NonNull Function<? super T,? extends MaybeSource<? extends R>> onSuccessMapper,
        @NonNull Function<? super Throwable,? extends MaybeSource<? extends R>> onErrorMapper,
        @NonNull Supplier<? extends MaybeSource<? extends R>> onCompleteSupplier)

Maps the onSuccess, onError or onComplete signals of the current Maybe into a MaybeSource and emits that MaybeSource's signals.

Scheduler:

flatMap does not operate by default on a particular Scheduler.

Type Parameters:

R - the result type

Parameters:

onSuccessMapper - a function that returns a MaybeSource to merge for the onSuccess item emitted by this Maybe

onErrorMapper - a function that returns a MaybeSource to merge for an onError notification from this Maybe

onCompleteSupplier - a function that returns a MaybeSource to merge for an onComplete notification this Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if onSuccessMapper, onErrorMapper or onCompleteSupplier is null

See Also:

ReactiveX operators documentation: FlatMap

flatMap

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U,R> @NonNull Maybe<R> flatMap(@NonNull Function<? super T,? extends MaybeSource<? extends U>> mapper,
        @NonNull BiFunction<? super T,? super U,? extends R> combiner)

Returns a Maybe that emits the results of a specified function to the pair of values emitted by the current Maybe and a specified mapped MaybeSource.

Scheduler:

flatMap does not operate by default on a particular Scheduler.

Type Parameters:

U - the type of items emitted by the MaybeSource returned by the mapper function

R - the type of items emitted by the resulting Maybe

Parameters:

mapper - a function that returns a MaybeSource for the item emitted by the current Maybe

combiner - a function that combines one item emitted by each of the source and collection MaybeSource and returns an item to be emitted by the resulting MaybeSource

Returns:

the new Maybe instance

Throws:

NullPointerException - if mapper or combiner is null

See Also:

ReactiveX operators documentation: FlatMap

flattenAsFlowable

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Flowable<U> flattenAsFlowable(@NonNull Function<? super T,? extends Iterable<? extends U>> mapper)

Maps the success value of the current Maybe into an Iterable and emits its items as a Flowable sequence.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

flattenAsFlowable does not operate by default on a particular Scheduler.

Type Parameters:

U - the type of item emitted by the inner Iterable

Parameters:

mapper - a function that returns an Iterable sequence of values for when given an item emitted by the current Maybe

Returns:

the new Flowable instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: FlatMap, flattenStreamAsFlowable(Function)

flattenAsObservable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Observable<U> flattenAsObservable(@NonNull Function<? super T,? extends Iterable<? extends U>> mapper)

Maps the success value of the current Maybe into an Iterable and emits its items as an Observable sequence.

Scheduler:

flattenAsObservable does not operate by default on a particular Scheduler.

Type Parameters:

U - the type of item emitted by the resulting Iterable

Parameters:

mapper - a function that returns an Iterable sequence of values for when given an item emitted by the current Maybe

Returns:

the new Observable instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: FlatMap

flatMapObservable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Observable<R> flatMapObservable(@NonNull Function<? super T,? extends ObservableSource<? extends R>> mapper)

Returns an Observable that is based on applying a specified function to the item emitted by the current Maybe, where that function returns an ObservableSource.

Scheduler:

flatMapObservable does not operate by default on a particular Scheduler.

Type Parameters:

R - the result value type

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns an ObservableSource

Returns:

the new Observable instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: FlatMap

flatMapPublisher

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Flowable<R> flatMapPublisher(@NonNull Function<? super T,? extends Publisher<? extends R>> mapper)

Returns a Flowable that emits items based on applying a specified function to the item emitted by the current Maybe, where that function returns a Publisher.

Backpressure:

The returned Flowable honors the downstream backpressure.

Scheduler:

flatMapPublisher does not operate by default on a particular Scheduler.

Type Parameters:

R - the result value type

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns a Flowable

Returns:

the new Flowable instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: FlatMap

flatMapSingle

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> flatMapSingle(@NonNull Function<? super T,? extends SingleSource<? extends R>> mapper)

Returns a Maybe based on applying a specified function to the item emitted by the current Maybe, where that function returns a Single. When this Maybe just completes the resulting Maybe completes as well.

Scheduler:

flatMapSingle does not operate by default on a particular Scheduler.

History: 2.0.2 - experimental

Type Parameters:

R - the result value type

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns a Single

Returns:

the new Maybe instance

Throws:

NullPointerException - if mapper is null

Since:

2.1

See Also:

ReactiveX operators documentation: FlatMap

flatMapCompletable

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Completable flatMapCompletable(@NonNull Function<? super T,? extends CompletableSource> mapper)

Returns a Completable that completes based on applying a specified function to the item emitted by the current Maybe, where that function returns a Completable.

Scheduler:

flatMapCompletable does not operate by default on a particular Scheduler.

Parameters:

mapper - a function that, when applied to the item emitted by the current Maybe, returns a Completable

Returns:

the new Completable instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: FlatMap

hide

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> hide()

Hides the identity of this Maybe and its Disposable.

Allows preventing certain identity-based optimizations (fusion).

Scheduler:

hide does not operate by default on a particular Scheduler.

Returns:

the new Maybe instance

ignoreElement

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Completable ignoreElement()

Returns a Completable that ignores the item emitted by the current Maybe and only calls onComplete or onError.

Scheduler:

ignoreElement does not operate by default on a particular Scheduler.

Returns:

the new Completable instance

See Also:

ReactiveX operators documentation: IgnoreElements

isEmpty

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Single<Boolean> isEmpty()

Returns a Single that emits true if the current Maybe is empty, otherwise false.

Scheduler:

isEmpty does not operate by default on a particular Scheduler.

Returns:

the new Single instance

See Also:

ReactiveX operators documentation: Contains

lift

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> lift(@NonNull MaybeOperator<? extends R,? super T> lift)

This method requires advanced knowledge about building operators, please consider other standard composition methods first; Returns a Maybe which, when subscribed to, invokes the apply(MaybeObserver) method of the provided MaybeOperator for each individual downstream Maybe and allows the insertion of a custom operator by accessing the downstream's MaybeObserver during this subscription phase and providing a new MaybeObserver, containing the custom operator's intended business logic, that will be used in the subscription process going further upstream.

Generally, such a new MaybeObserver will wrap the downstream's MaybeObserver and forwards the onSuccess, onError and onComplete events from the upstream directly or according to the emission pattern the custom operator's business logic requires. In addition, such operator can intercept the flow control calls of dispose and isDisposed that would have traveled upstream and perform additional actions depending on the same business logic requirements.

Example:

 // Step 1: Create the consumer type that will be returned by the MaybeOperator.apply():
 
 public final class CustomMaybeObserver<T> implements MaybeObserver<T>, Disposable {

     // The downstream's MaybeObserver that will receive the onXXX events
     final MaybeObserver<? super String> downstream;

     // The connection to the upstream source that will call this class' onXXX methods
     Disposable upstream;

     // The constructor takes the downstream subscriber and usually any other parameters
     public CustomMaybeObserver(MaybeObserver<? super String> downstream) {
         this.downstream = downstream;
     }

     // In the subscription phase, the upstream sends a Disposable to this class
     // and subsequently this class has to send a Disposable to the downstream.
     // Note that relaying the upstream's Disposable directly is not allowed in RxJava
     @Override
     public void onSubscribe(Disposable d) {
         if (upstream != null) {
             d.dispose();
         } else {
             upstream = d;
             downstream.onSubscribe(this);
         }
     }

     // The upstream calls this with the next item and the implementation's
     // responsibility is to emit an item to the downstream based on the intended
     // business logic, or if it can't do so for the particular item,
        // request more from the upstream
     @Override
     public void onSuccess(T item) {
         String str = item.toString();
         if (str.length() < 2) {
             downstream.onSuccess(str);
         } else {
             // Maybe is expected to produce one of the onXXX events only
             downstream.onComplete();
         }
     }

     // Some operators may handle the upstream's error while others
     // could just forward it to the downstream.
     @Override
     public void onError(Throwable throwable) {
         downstream.onError(throwable);
     }

     // When the upstream completes, usually the downstream should complete as well.
     @Override
     public void onComplete() {
         downstream.onComplete();
     }

     // Some operators may use their own resources which should be cleaned up if
     // the downstream disposes the flow before it completed. Operators without
     // resources can simply forward the dispose to the upstream.
     // In some cases, a disposed flag may be set by this method so that other parts
     // of this class may detect the dispose and stop sending events
     // to the downstream.
     @Override
     public void dispose() {
         upstream.dispose();
     }

     // Some operators may simply forward the call to the upstream while others
     // can return the disposed flag set in dispose().
     @Override
     public boolean isDisposed() {
         return upstream.isDisposed();
     }
 }

 // Step 2: Create a class that implements the MaybeOperator interface and
 //         returns the custom consumer type from above in its apply() method.
 //         Such class may define additional parameters to be submitted to
 //         the custom consumer type.

 final class CustomMaybeOperator<T> implements MaybeOperator<String> {
     @Override
     public MaybeObserver<? super String> apply(MaybeObserver<? super T> upstream) {
         return new CustomMaybeObserver<T>(upstream);
     }
 }

 // Step 3: Apply the custom operator via lift() in a flow by creating an instance of it
 //         or reusing an existing one.

 Maybe.just(5)
 .lift(new CustomMaybeOperator<Integer>())
 .test()
 .assertResult("5");

 Maybe.just(15)
 .lift(new CustomMaybeOperator<Integer>())
 .test()
 .assertResult();
 

Creating custom operators can be complicated and it is recommended one consults the RxJava wiki: Writing operators page about the tools, requirements, rules, considerations and pitfalls of implementing them.

Note that implementing custom operators via this lift() method adds slightly more overhead by requiring an additional allocation and indirection per assembled flows. Instead, extending the abstract Maybe class and creating a MaybeTransformer with it is recommended.

Note also that it is not possible to stop the subscription phase in lift() as the apply() method requires a non-null MaybeObserver instance to be returned, which is then unconditionally subscribed to the current Maybe. For example, if the operator decided there is no reason to subscribe to the upstream source because of some optimization possibility or a failure to prepare the operator, it still has to return a MaybeObserver that should immediately dispose the upstream's Disposable in its onSubscribe method. Again, using a MaybeTransformer and extending the Maybe is a better option as subscribeActual(io.reactivex.rxjava3.core.MaybeObserver<? super T>) can decide to not subscribe to its upstream after all.

Scheduler:

lift does not operate by default on a particular Scheduler, however, the MaybeOperator may use a Scheduler to support its own asynchronous behavior.

Type Parameters:

R - the output value type

Parameters:

lift - the MaybeOperator that receives the downstream's MaybeObserver and should return a MaybeObserver with custom behavior to be used as the consumer for the current Maybe.

Returns:

the new Maybe instance

Throws:

NullPointerException - if lift is null

See Also:

RxJava wiki: Writing operators, compose(MaybeTransformer)

map

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <R> @NonNull Maybe<R> map(@NonNull Function<? super T,? extends R> mapper)

Returns a Maybe that applies a specified function to the item emitted by the current Maybe and emits the result of this function application.

Scheduler:

map does not operate by default on a particular Scheduler.

Type Parameters:

R - the result value type

Parameters:

mapper - a function to apply to the item emitted by the Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if mapper is null

See Also:

ReactiveX operators documentation: Map

materialize

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Single<Notification<T>> materialize()

Maps the signal types of this Maybe into a Notification of the same kind and emits it as a Single's onSuccess value to downstream.

Scheduler:

materialize does not operate by default on a particular Scheduler.

History: 2.2.4 - experimental

Returns:

the new Single instance

Since:

3.0.0

See Also:

Single.dematerialize(Function)

mergeWith

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Flowable<T> mergeWith(@NonNull MaybeSource<? extends T> other)

Flattens this Maybe and another MaybeSource into a single Flowable, without any transformation.

You can combine items emitted by multiple Maybes so that they appear as a single Flowable, by using the mergeWith method.

Backpressure:

The operator honors backpressure from downstream.

Scheduler:

mergeWith does not operate by default on a particular Scheduler.

Parameters:

other - a MaybeSource to be merged

Returns:

the new Flowable instance

Throws:

NullPointerException - if other is null

See Also:

ReactiveX operators documentation: Merge

observeOn

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<T> observeOn(@NonNull Scheduler scheduler)

Wraps a Maybe to emit its item (or notify of its error) on a specified Scheduler, asynchronously.

Scheduler:

you specify which Scheduler this operator will use.

Parameters:

scheduler - the Scheduler to notify subscribers on

Returns:

the new Maybe instance that its subscribers are notified on the specified Scheduler

Throws:

NullPointerException - if scheduler is null

See Also:

ReactiveX operators documentation: ObserveOn, RxJava Threading Examples, subscribeOn(io.reactivex.rxjava3.core.Scheduler)

ofType

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<U> ofType(@NonNull Class<U> clazz)

Filters the items emitted by the current Maybe, only emitting its success value if that is an instance of the supplied Class.

Scheduler:

ofType does not operate by default on a particular Scheduler.

Type Parameters:

U - the output type

Parameters:

clazz - the class type to filter the items emitted by the current Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if clazz is null

See Also:

ReactiveX operators documentation: Filter

to

@CheckReturnValue
 @SchedulerSupport(value="none")
public final <R> R to(@NonNull MaybeConverter<T,? extends R> converter)

Calls the specified converter function during assembly time and returns its resulting value.

This allows fluent conversion to any other type.

Scheduler:

to does not operate by default on a particular Scheduler.

History: 2.1.7 - experimental

Type Parameters:

R - the resulting object type

Parameters:

converter - the function that receives the current Maybe instance and returns a value

Returns:

the converted value

Throws:

NullPointerException - if converter is null

Since:

2.2

toFlowable

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Flowable<T> toFlowable()

Converts this Maybe into a backpressure-aware Flowable instance composing cancellation through.

Backpressure:

The returned Flowable honors the backpressure of the downstream.

Scheduler:

toFlowable does not operate by default on a particular Scheduler.

Returns:

the new Flowable instance

toFuture

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Future<T> toFuture()

Returns a Future representing the single value emitted by the current Maybe or null if the current Maybe is empty.

Cancelling the Future will cancel the subscription to the current Maybe.

Scheduler:

toFuture does not operate by default on a particular Scheduler.

Returns:

the new Future instance

Since:

3.0.0

See Also:

ReactiveX documentation: To

toObservable

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Observable<T> toObservable()

Converts this Maybe into an Observable instance composing disposal through.

Scheduler:

toObservable does not operate by default on a particular Scheduler.

Returns:

the new Observable instance

toSingle

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Single<T> toSingle()

Converts this Maybe into a Single instance composing disposal through and turning an empty Maybe into a signal of NoSuchElementException.

Scheduler:

toSingle does not operate by default on a particular Scheduler.

Returns:

the new Single instance

See Also:

defaultIfEmpty(Object)

onErrorComplete

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> onErrorComplete()

Returns a Maybe instance that if this Maybe emits an error, it will emit an onComplete and swallow the throwable.

Scheduler:

onErrorComplete does not operate by default on a particular Scheduler.

Returns:

the new Maybe instance

onErrorComplete

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> onErrorComplete(@NonNull Predicate<? super Throwable> predicate)

Returns a Maybe instance that if this Maybe emits an error and the predicate returns true, it will emit an onComplete and swallow the throwable.

Scheduler:

onErrorComplete does not operate by default on a particular Scheduler.

Parameters:

predicate - the predicate to call when an Throwable is emitted which should return true if the Throwable should be swallowed and replaced with an onComplete.

Returns:

the new Maybe instance

Throws:

NullPointerException - if predicate is null

onErrorResumeWith

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> onErrorResumeWith(@NonNull MaybeSource<? extends T> fallback)

Resumes the flow with the given MaybeSource when the current Maybe fails instead of signaling the error via onError.

You can use this to prevent errors from propagating or to supply fallback data should errors be encountered.

Scheduler:

onErrorResumeWith does not operate by default on a particular Scheduler.

Parameters:

fallback - the next MaybeSource that will take over if the current Maybe encounters an error

Returns:

the new Maybe instance

Throws:

NullPointerException - if fallback is null

See Also:

ReactiveX operators documentation: Catch

onErrorResumeNext

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> onErrorResumeNext(@NonNull Function<? super Throwable,? extends MaybeSource<? extends T>> fallbackSupplier)

Resumes the flow with a MaybeSource returned for the failure Throwable of the current Maybe by a function instead of signaling the error via onError.

You can use this to prevent errors from propagating or to supply fallback data should errors be encountered.

Scheduler:

onErrorResumeNext does not operate by default on a particular Scheduler.

Parameters:

fallbackSupplier - a function that returns a MaybeSource that will take over if the current Maybe encounters an error

Returns:

the new Maybe instance

Throws:

NullPointerException - if fallbackSupplier is null

See Also:

ReactiveX operators documentation: Catch

onErrorReturn

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> onErrorReturn(@NonNull Function<? super Throwable,? extends T> itemSupplier)

Ends the flow with a success item returned by a function for the Throwable error signaled by the current Maybe instead of signaling the error via onError.

You can use this to prevent errors from propagating or to supply fallback data should errors be encountered.

Scheduler:

onErrorReturn does not operate by default on a particular Scheduler.

Parameters:

itemSupplier - a function that returns a single value that will be emitted as success value the current Maybe signals an onError event

Returns:

the new Maybe instance

Throws:

NullPointerException - if itemSupplier is null

See Also:

ReactiveX operators documentation: Catch

onErrorReturnItem

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> onErrorReturnItem(@NonNull T item)

Ends the flow with the given success item when the current Maybe fails instead of signaling the error via onError.

You can use this to prevent errors from propagating or to supply fallback data should errors be encountered.

Scheduler:

onErrorReturnItem does not operate by default on a particular Scheduler.

Parameters:

item - the value that is emitted as onSuccess in case the current Maybe signals an onError

Returns:

the new Maybe instance

Throws:

NullPointerException - if item is null

See Also:

ReactiveX operators documentation: Catch

onTerminateDetach

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> onTerminateDetach()

Nulls out references to the upstream producer and downstream MaybeObserver if the sequence is terminated or downstream calls dispose().

Scheduler:

onTerminateDetach does not operate by default on a particular Scheduler.

Returns:

the new Maybe instance the sequence is terminated or downstream calls dispose()

repeat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Flowable<T> repeat()

Returns a Flowable that repeats the sequence of items emitted by the current Maybe indefinitely.

Backpressure:

The operator honors downstream backpressure.

Scheduler:

repeat does not operate by default on a particular Scheduler.

Returns:

the new Flowable instance

See Also:

ReactiveX operators documentation: Repeat

repeat

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Flowable<T> repeat(long times)

Returns a Flowable that repeats the sequence of items emitted by the current Maybe at most count times.

Backpressure:

This operator honors downstream backpressure.

Scheduler:

repeat does not operate by default on a particular Scheduler.

Parameters:

times - the number of times the current Maybe items are repeated, a count of 0 will yield an empty sequence

Returns:

the new Flowable instance

Throws:

IllegalArgumentException - if times is negative

See Also:

ReactiveX operators documentation: Repeat

repeatUntil

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Flowable<T> repeatUntil(@NonNull BooleanSupplier stop)

Returns a Flowable that repeats the sequence of items emitted by the current Maybe until the provided stop function returns true.

Backpressure:

This operator honors downstream backpressure.

Scheduler:

repeatUntil does not operate by default on a particular Scheduler.

Parameters:

stop - a boolean supplier that is called when the current Flowable completes and unless it returns false, the current Flowable is resubscribed

Returns:

the new Flowable instance

Throws:

NullPointerException - if stop is null

See Also:

ReactiveX operators documentation: Repeat

repeatWhen

@BackpressureSupport(value=FULL)
 @CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Flowable<T> repeatWhen(@NonNull Function<? super Flowable<Object>,? extends Publisher<?>> handler)

Returns a Flowable that emits the same values as the current Maybe with the exception of an onComplete. An onComplete notification from the source will result in the emission of a void item to the Flowable provided as an argument to the notificationHandler function. If that Publisher calls onComplete or onError then repeatWhen will call onComplete or onError on the child observer. Otherwise, this operator will resubscribe to the current Maybe.

Backpressure:

The operator honors downstream backpressure and expects the source Publisher to honor backpressure as well. If this expectation is violated, the operator may throw an IllegalStateException.

Scheduler:

repeatWhen does not operate by default on a particular Scheduler.

Parameters:

handler - receives a Publisher of notifications with which a user can complete or error, aborting the repeat.

Returns:

the new Flowable instance

Throws:

NullPointerException - if handler is null

See Also:

ReactiveX operators documentation: Repeat

retry

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> retry()

Returns a Maybe that mirrors the current Maybe, resubscribing to it if it calls onError (infinite retry count).

If the current Maybe calls MaybeObserver.onError(java.lang.Throwable), this operator will resubscribe to the current Maybe rather than propagating the onError call.

Scheduler:

retry does not operate by default on a particular Scheduler.

Returns:

the new Maybe instance

See Also:

ReactiveX operators documentation: Retry

retry

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> retry(@NonNull BiPredicate<? super Integer,? super Throwable> predicate)

Returns a Maybe that mirrors the current Maybe, resubscribing to it if it calls onError and the predicate returns true for that specific exception and retry count.

Scheduler:

retry does not operate by default on a particular Scheduler.

Parameters:

predicate - the predicate that determines if a resubscription may happen in case of a specific exception and retry count

Returns:

the new Maybe instance

Throws:

NullPointerException - if predicate is null

See Also:

retry(), ReactiveX operators documentation: Retry

retry

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> retry(long times)

Returns a Maybe that mirrors the current Maybe, resubscribing to it if it calls onError up to a specified number of retries.

If the current Maybe calls MaybeObserver.onError(java.lang.Throwable), this operator will resubscribe to the current Maybe for a maximum of count resubscriptions rather than propagating the onError call.

Scheduler:

retry does not operate by default on a particular Scheduler.

Parameters:

times - the number of times to resubscribe if the current Maybe fails

Returns:

the new Maybe instance

Throws:

IllegalArgumentException - if times is negative

See Also:

ReactiveX operators documentation: Retry

retry

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> retry(long times,
        @NonNull Predicate<? super Throwable> predicate)

Retries at most times or until the predicate returns false, whichever happens first.

Scheduler:

retry does not operate by default on a particular Scheduler.

Parameters:

times - the number of times to resubscribe if the current Maybe fails

predicate - the predicate called with the failure Throwable and should return true to trigger a retry.

Returns:

the new Maybe instance

Throws:

NullPointerException - if predicate is null

IllegalArgumentException - if times is negative

retry

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> retry(@NonNull Predicate<? super Throwable> predicate)

Retries the current Maybe if it fails and the predicate returns true.

Scheduler:

retry does not operate by default on a particular Scheduler.

Parameters:

predicate - the predicate that receives the failure Throwable and should return true to trigger a retry.

Returns:

the new Maybe instance

Throws:

NullPointerException - if predicate is null

retryUntil

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> retryUntil(@NonNull BooleanSupplier stop)

Retries until the given stop function returns true.

Scheduler:

retryUntil does not operate by default on a particular Scheduler.

Parameters:

stop - the function that should return true to stop retrying

Returns:

the new Maybe instance

Throws:

NullPointerException - if stop is null

retryWhen

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Maybe<T> retryWhen(@NonNull Function<? super Flowable<Throwable>,? extends Publisher<?>> handler)

Returns a Maybe that emits the same values as the current Maybe with the exception of an onError. An onError notification from the source will result in the emission of a Throwable item to the Flowable provided as an argument to the notificationHandler function. If the returned Publisher calls onComplete or onError then retry will call onComplete or onError on the child subscription. Otherwise, this operator will resubscribe to the current Maybe.

Example: This retries 3 times, each time incrementing the number of seconds it waits.

  Maybe.create((MaybeEmitter<? super String> s) -> {
      System.out.println("subscribing");
      s.onError(new RuntimeException("always fails"));
  }, BackpressureStrategy.BUFFER).retryWhen(attempts -> {
      return attempts.zipWith(Publisher.range(1, 3), (n, i) -> i).flatMap(i -> {
          System.out.println("delay retry by " + i + " second(s)");
          return Flowable.timer(i, TimeUnit.SECONDS);
      });
  }).blockingForEach(System.out::println);
 

Output is:

 
 subscribing
 delay retry by 1 second(s)
 subscribing
 delay retry by 2 second(s)
 subscribing
 delay retry by 3 second(s)
 subscribing
  

Note that the inner Publisher returned by the handler function should signal either onNext, onError or onComplete in response to the received Throwable to indicate the operator should retry or terminate. If the upstream to the operator is asynchronous, signalling onNext followed by onComplete immediately may result in the sequence to be completed immediately. Similarly, if this inner Publisher signals onError or onComplete while the upstream is active, the sequence is terminated with the same signal immediately.

The following example demonstrates how to retry an asynchronous source with a delay:

 Maybe.timer(1, TimeUnit.SECONDS)
     .doOnSubscribe(s -> System.out.println("subscribing"))
     .map(v -> { throw new RuntimeException(); })
     .retryWhen(errors -> {
         AtomicInteger counter = new AtomicInteger();
         return errors
                   .takeWhile(e -> counter.getAndIncrement() != 3)
                   .flatMap(e -> {
                       System.out.println("delay retry by " + counter.get() + " second(s)");
                       return Flowable.timer(counter.get(), TimeUnit.SECONDS);
                   });
     })
     .blockingGet();
 

Scheduler:

retryWhen does not operate by default on a particular Scheduler.

Parameters:

handler - receives a Publisher of notifications with which a user can complete or error, aborting the retry

Returns:

the new Maybe instance

Throws:

NullPointerException - if handler is null

See Also:

ReactiveX operators documentation: Retry

safeSubscribe

@SchedulerSupport(value="none")
public final void safeSubscribe(@NonNull MaybeObserver<? super T> observer)

Wraps the given MaybeObserver, catches any RuntimeExceptions thrown by its MaybeObserver.onSubscribe(Disposable), MaybeObserver.onSuccess(Object), MaybeObserver.onError(Throwable) or MaybeObserver.onComplete() methods and routes those to the global error handler via RxJavaPlugins.onError(Throwable).

By default, the Maybe protocol forbids the onXXX methods to throw, but some MaybeObserver implementation may do it anyway, causing undefined behavior in the upstream. This method and the underlying safe wrapper ensures such misbehaving consumers don't disrupt the protocol.

Scheduler:

safeSubscribe does not operate by default on a particular Scheduler.

Parameters:

observer - the potentially misbehaving MaybeObserver

Throws:

NullPointerException - if observer is null

Since:

3.0.0

See Also:

subscribe(Consumer,Consumer, Action)

startWith

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @BackpressureSupport(value=FULL)
public final @NonNull Flowable<T> startWith(@NonNull CompletableSource other)

Returns a Flowable which first runs the other CompletableSource then the current Maybe if the other completed normally.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

startWith does not operate by default on a particular Scheduler.

Parameters:

other - the other CompletableSource to run first

Returns:

the new Flowable instance

Throws:

NullPointerException - if other is null

Since:

3.0.0

startWith

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @BackpressureSupport(value=FULL)
public final @NonNull Flowable<T> startWith(@NonNull SingleSource<T> other)

Returns a Flowable which first runs the other SingleSource then the current Maybe if the other succeeded normally.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

startWith does not operate by default on a particular Scheduler.

Parameters:

other - the other SingleSource to run first

Returns:

the new Flowable instance

Throws:

NullPointerException - if other is null

Since:

3.0.0

startWith

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
 @BackpressureSupport(value=FULL)
public final @NonNull Flowable<T> startWith(@NonNull MaybeSource<T> other)

Returns a Flowable which first runs the other MaybeSource then the current Maybe if the other succeeded or completed normally.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer.

Scheduler:

startWith does not operate by default on a particular Scheduler.

Parameters:

other - the other MaybeSource to run first

Returns:

the new Flowable instance

Throws:

NullPointerException - if other is null

Since:

3.0.0

startWith

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Observable<T> startWith(@NonNull ObservableSource<T> other)

Returns an Observable which first delivers the events of the other ObservableSource then runs the current Maybe.

Scheduler:

startWith does not operate by default on a particular Scheduler.

Parameters:

other - the other ObservableSource to run first

Returns:

the new Observable instance

Throws:

NullPointerException - if other is null

Since:

3.0.0

startWith

@CheckReturnValue
 @NonNull
 @BackpressureSupport(value=FULL)
 @SchedulerSupport(value="none")
public final @NonNull Flowable<T> startWith(@NonNull Publisher<T> other)

Returns a Flowable which first delivers the events of the other Publisher then runs the current Maybe.

Backpressure:

The returned Flowable honors the backpressure of the downstream consumer and expects the other Publisher to honor it as well.

Scheduler:

startWith does not operate by default on a particular Scheduler.

Parameters:

other - the other Publisher to run first

Returns:

the new Flowable instance

Throws:

NullPointerException - if other is null

Since:

3.0.0

subscribe

@SchedulerSupport(value="none")
 @NonNull
public final @NonNull Disposable subscribe()

Subscribes to a Maybe and ignores onSuccess and onComplete emissions.

If the Maybe emits an error, it is wrapped into an OnErrorNotImplementedException and routed to the RxJavaPlugins.onError(Throwable) handler.

Scheduler:

subscribe does not operate by default on a particular Scheduler.

Returns:

the new Disposable instance that can be used for disposing the subscription at any time

See Also:

ReactiveX operators documentation: Subscribe, subscribe(Consumer, Consumer, Action, DisposableContainer)

subscribe

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Disposable subscribe(@NonNull Consumer<? super T> onSuccess)

Subscribes to a Maybe and provides a callback to handle the items it emits.

If the Maybe emits an error, it is wrapped into an OnErrorNotImplementedException and routed to the RxJavaPlugins.onError(Throwable) handler.

Scheduler:

subscribe does not operate by default on a particular Scheduler.

Parameters:

onSuccess - the Consumer<T> you have designed to accept a success value from the Maybe

Returns:

the new Disposable instance that can be used for disposing the subscription at any time

Throws:

NullPointerException - if onSuccess is null

See Also:

ReactiveX operators documentation: Subscribe, subscribe(Consumer, Consumer, Action, DisposableContainer)

subscribe

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull Disposable subscribe(@NonNull Consumer<? super T> onSuccess,
        @NonNull Consumer<? super Throwable> onError)

Subscribes to a Maybe and provides callbacks to handle the items it emits and any error notification it issues.

Scheduler:

subscribe does not operate by default on a particular Scheduler.

Parameters:

onSuccess - the Consumer<T> you have designed to accept a success value from the Maybe

onError - the Consumer<Throwable> you have designed to accept any error notification from the Maybe

Returns:

the new Disposable instance that can be used for disposing the subscription at any time

Throws:

NullPointerException - if onSuccess is null, or if onError is null

See Also:

ReactiveX operators documentation: Subscribe, subscribe(Consumer, Consumer, Action, DisposableContainer)

subscribe

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Disposable subscribe(@NonNull Consumer<? super T> onSuccess,
        @NonNull Consumer<? super Throwable> onError,
        @NonNull Action onComplete)

Subscribes to a Maybe and provides callbacks to handle the items it emits and any error or completion notification it issues.

Scheduler:

subscribe does not operate by default on a particular Scheduler.

Parameters:

onSuccess - the Consumer<T> you have designed to accept a success value from the Maybe

onError - the Consumer<Throwable> you have designed to accept any error notification from the Maybe

onComplete - the Action you have designed to accept a completion notification from the Maybe

Returns:

the new Disposable instance that can be used for disposing the subscription at any time

Throws:

NullPointerException - if onSuccess, onError or onComplete is null

See Also:

ReactiveX operators documentation: Subscribe, subscribe(Consumer, Consumer, Action, DisposableContainer)

subscribe

@SchedulerSupport(value="none")
 @NonNull
public final @NonNull Disposable subscribe(@NonNull Consumer<? super T> onSuccess,
        @NonNull Consumer<? super Throwable> onError,
        @NonNull Action onComplete,
        @NonNull DisposableContainer container)

Wraps the given onXXX callbacks into a Disposable MaybeObserver, adds it to the given DisposableContainer and ensures, that if the upstream terminates or this particular Disposable is disposed, the MaybeObserver is removed from the given composite.

The MaybeObserver will be removed after the callback for the terminal event has been invoked.

Scheduler:

subscribe does not operate by default on a particular Scheduler.

Parameters:

onSuccess - the callback for upstream items

onError - the callback for an upstream error

onComplete - the callback for an upstream completion without any value or error

container - the DisposableContainer (such as CompositeDisposable) to add and remove the created Disposable MaybeObserver

Returns:

the Disposable that allows disposing the particular subscription.

Throws:

NullPointerException - if onSuccess, onError, onComplete or container is null

Since:

3.1.0

subscribe

@SchedulerSupport(value="none")
public final void subscribe(@NonNull MaybeObserver<? super T> observer)

Description copied from interface: MaybeSource

Subscribes the given MaybeObserver to this MaybeSource instance.

Specified by:

subscribe in interface MaybeSource<T>

Parameters:

observer - the MaybeObserver, not null

subscribeActual

protected abstract void subscribeActual(@NonNull MaybeObserver<? super T> observer)

Implement this method in subclasses to handle the incoming MaybeObservers.

There is no need to call any of the plugin hooks on the current Maybe instance or the MaybeObserver; all hooks and basic safeguards have been applied by subscribe(MaybeObserver) before this method gets called.

Parameters:

observer - the MaybeObserver to handle, not null

subscribeOn

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<T> subscribeOn(@NonNull Scheduler scheduler)

Asynchronously subscribes subscribers to this Maybe on the specified Scheduler.

Scheduler:

you specify which Scheduler this operator will use.

Parameters:

scheduler - the Scheduler to perform subscription actions on

Returns:

the new Maybe instance

Throws:

NullPointerException - if scheduler is null

See Also:

ReactiveX operators documentation: SubscribeOn, RxJava Threading Examples, observeOn(io.reactivex.rxjava3.core.Scheduler)

subscribeWith

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final <E extends MaybeObserver<? super T>> E subscribeWith(E observer)

Subscribes a given MaybeObserver (subclass) to this Maybe and returns the given MaybeObserver as is.

Usage example:

 Maybe<Integer> source = Maybe.just(1);
 CompositeDisposable composite = new CompositeDisposable();

 DisposableMaybeObserver<Integer> ds = new DisposableMaybeObserver<>() {
     // ...
 };

 composite.add(source.subscribeWith(ds));
 

Scheduler:

subscribeWith does not operate by default on a particular Scheduler.

Type Parameters:

E - the type of the MaybeObserver to use and return

Parameters:

observer - the MaybeObserver (subclass) to use and return, not null

Returns:

the input observer

Throws:

NullPointerException - if observer is null

switchIfEmpty

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Maybe<T> switchIfEmpty(@NonNull MaybeSource<? extends T> other)

Returns a Maybe that emits the items emitted by the current Maybe or the items of an alternate MaybeSource if the current Maybe is empty.

Scheduler:

switchIfEmpty does not operate by default on a particular Scheduler.

Parameters:

other - the alternate MaybeSource to subscribe to if the main does not emit any items

Returns:

the new Maybe instance

Throws:

NullPointerException - if other is null

switchIfEmpty

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final @NonNull Single<T> switchIfEmpty(@NonNull SingleSource<? extends T> other)

Returns a Single that emits the items emitted by the current Maybe or the item of an alternate SingleSource if the current Maybe is empty.

Scheduler:

switchIfEmpty does not operate by default on a particular Scheduler.

History: 2.1.4 - experimental

Parameters:

other - the alternate SingleSource to subscribe to if the main does not emit any items

Returns:

the new Single instance

Throws:

NullPointerException - if other is null

Since:

2.2

takeUntil

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<T> takeUntil(@NonNull MaybeSource<U> other)

Returns a Maybe that emits the items emitted by the current Maybe until a second MaybeSource emits an item.

Scheduler:

takeUntil does not operate by default on a particular Scheduler.

Type Parameters:

U - the type of items emitted by other

Parameters:

other - the MaybeSource whose first emitted item will cause takeUntil to stop emitting items from the current Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if other is null

See Also:

ReactiveX operators documentation: TakeUntil

takeUntil

@BackpressureSupport(value=UNBOUNDED_IN)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<T> takeUntil(@NonNull Publisher<U> other)

Returns a Maybe that emits the item emitted by the current Maybe until a second Publisher emits an item.

Backpressure:

The Publisher is consumed in an unbounded fashion and is cancelled after the first item emitted.

Scheduler:

takeUntil does not operate by default on a particular Scheduler.

Type Parameters:

U - the type of items emitted by other

Parameters:

other - the Publisher whose first emitted item will cause takeUntil to stop emitting items from the source Publisher

Returns:

the new Maybe instance

Throws:

NullPointerException - if other is null

See Also:

ReactiveX operators documentation: TakeUntil

timeInterval

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="io.reactivex:computation")
public final @NonNull Maybe<Timed<T>> timeInterval()

Measures the time (in milliseconds) between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timeInterval().

Scheduler:

timeInterval uses the computation Scheduler for determining the current time upon subscription and upon receiving the success item from the current Maybe.

Returns:

the new Maybe instance

Since:

3.0.0

timeInterval

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<Timed<T>> timeInterval(@NonNull Scheduler scheduler)

Measures the time (in milliseconds) between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timeInterval(Scheduler).

Scheduler:

timeInterval uses the provided Scheduler for determining the current time upon subscription and upon receiving the success item from the current Maybe.

Parameters:

scheduler - the Scheduler used for providing the current time

Returns:

the new Maybe instance

Throws:

NullPointerException - if scheduler is null

Since:

3.0.0

timeInterval

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="io.reactivex:computation")
public final @NonNull Maybe<Timed<T>> timeInterval(@NonNull TimeUnit unit)

Measures the time between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timeInterval(TimeUnit).

Scheduler:

timeInterval uses the computation Scheduler for determining the current time upon subscription and upon receiving the success item from the current Maybe.

Parameters:

unit - the time unit for measurement

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit is null

Since:

3.0.0

timeInterval

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<Timed<T>> timeInterval(@NonNull TimeUnit unit,
        @NonNull Scheduler scheduler)

Measures the time between the subscription and success item emission of the current Maybe and signals it as a tuple (Timed) success value.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timeInterval(TimeUnit, Scheduler).

Scheduler:

timeInterval uses the provided Scheduler for determining the current time upon subscription and upon receiving the success item from the current Maybe.

Parameters:

unit - the time unit for measurement

scheduler - the Scheduler used for providing the current time

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or scheduler is null

Since:

3.0.0

timestamp

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="io.reactivex:computation")
public final @NonNull Maybe<Timed<T>> timestamp()

Combines the success value from the current Maybe with the current time (in milliseconds) of its reception, using the computation Scheduler as time source, then signals them as a Timed instance.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timestamp().

Scheduler:

timestamp uses the computation Scheduler for determining the current time upon receiving the success item from the current Maybe.

Returns:

the new Maybe instance

Since:

3.0.0

timestamp

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<Timed<T>> timestamp(@NonNull Scheduler scheduler)

Combines the success value from the current Maybe with the current time (in milliseconds) of its reception, using the given Scheduler as time source, then signals them as a Timed instance.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timestamp(Scheduler).

Scheduler:

timestamp uses the provided Scheduler for determining the current time upon receiving the success item from the current Maybe.

Parameters:

scheduler - the Scheduler used for providing the current time

Returns:

the new Maybe instance

Throws:

NullPointerException - if scheduler is null

Since:

3.0.0

timestamp

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="io.reactivex:computation")
public final @NonNull Maybe<Timed<T>> timestamp(@NonNull TimeUnit unit)

Combines the success value from the current Maybe with the current time of its reception, using the computation Scheduler as time source, then signals it as a Timed instance.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timestamp(TimeUnit).

Scheduler:

timestamp uses the computation Scheduler, for determining the current time upon receiving the success item from the current Maybe.

Parameters:

unit - the time unit for measurement

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit is null

Since:

3.0.0

timestamp

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<Timed<T>> timestamp(@NonNull TimeUnit unit,
        @NonNull Scheduler scheduler)

Combines the success value from the current Maybe with the current time of its reception, using the given Scheduler as time source, then signals it as a Timed instance.

If the current Maybe is empty or fails, the resulting Maybe will pass along the signals to the downstream. To measure the time to termination, use materialize() and apply Single.timestamp(TimeUnit, Scheduler).

Scheduler:

timestamp uses the provided Scheduler, which is used for determining the current time upon receiving the success item from the current Maybe.

Parameters:

unit - the time unit for measurement

scheduler - the Scheduler used for providing the current time

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or scheduler is null

Since:

3.0.0

timeout

@CheckReturnValue
 @SchedulerSupport(value="io.reactivex:computation")
 @NonNull
public final @NonNull Maybe<T> timeout(long timeout,
        @NonNull TimeUnit unit)

Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item. If the next item isn't emitted within the specified timeout duration starting from its predecessor, the resulting Maybe terminates and notifies MaybeObservers of a TimeoutException.

Scheduler:

This version of timeout operates by default on the computation Scheduler.

Parameters:

timeout - maximum duration between emitted items before a timeout occurs

unit - the unit of time that applies to the timeout argument.

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit is null

See Also:

ReactiveX operators documentation: Timeout

timeout

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="io.reactivex:computation")
public final @NonNull Maybe<T> timeout(long timeout,
        @NonNull TimeUnit unit,
        @NonNull MaybeSource<? extends T> fallback)

Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item. If the next item isn't emitted within the specified timeout duration starting from its predecessor, the current Maybe is disposed and resulting Maybe begins instead to mirror a fallback MaybeSource.

Scheduler:

This version of timeout operates by default on the computation Scheduler.

Parameters:

timeout - maximum duration between items before a timeout occurs

unit - the unit of time that applies to the timeout argument

fallback - the fallback MaybeSource to use in case of a timeout

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or fallback is null

See Also:

ReactiveX operators documentation: Timeout

timeout

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<T> timeout(long timeout,
        @NonNull TimeUnit unit,
        @NonNull Scheduler scheduler,
        @NonNull MaybeSource<? extends T> fallback)

Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item using a specified Scheduler. If the next item isn't emitted within the specified timeout duration starting from its predecessor, the current Maybe is disposed and resulting Maybe begins instead to mirror a fallback MaybeSource.

Scheduler:

You specify which Scheduler this operator will use.

Parameters:

timeout - maximum duration between items before a timeout occurs

unit - the unit of time that applies to the timeout argument

fallback - the MaybeSource to use as the fallback in case of a timeout

scheduler - the Scheduler to run the timeout timers on

Returns:

the new Maybe instance

Throws:

NullPointerException - if fallback, unit or scheduler is null

See Also:

ReactiveX operators documentation: Timeout

timeout

@CheckReturnValue
 @SchedulerSupport(value="custom")
 @NonNull
public final @NonNull Maybe<T> timeout(long timeout,
        @NonNull TimeUnit unit,
        @NonNull Scheduler scheduler)

Returns a Maybe that mirrors the current Maybe but applies a timeout policy for each emitted item, where this policy is governed on a specified Scheduler. If the next item isn't emitted within the specified timeout duration starting from its predecessor, the resulting Maybe terminates and notifies MaybeObservers of a TimeoutException.

Scheduler:

You specify which Scheduler this operator will use.

Parameters:

timeout - maximum duration between items before a timeout occurs

unit - the unit of time that applies to the timeout argument

scheduler - the Scheduler to run the timeout timers on

Returns:

the new Maybe instance

Throws:

NullPointerException - if unit or scheduler is null

See Also:

ReactiveX operators documentation: Timeout

timeout

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<T> timeout(@NonNull MaybeSource<U> timeoutIndicator)

If the current Maybe didn't signal an event before the timeoutIndicator MaybeSource signals, a TimeoutException is signaled instead.

Scheduler:

timeout does not operate by default on a particular Scheduler.

Type Parameters:

U - the value type of the

Parameters:

timeoutIndicator - the MaybeSource that indicates the timeout by signaling onSuccess or onComplete.

Returns:

the new Maybe instance

Throws:

NullPointerException - if timeoutIndicator is null

timeout

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<T> timeout(@NonNull MaybeSource<U> timeoutIndicator,
        @NonNull MaybeSource<? extends T> fallback)

If the current Maybe didn't signal an event before the timeoutIndicator MaybeSource signals, the current Maybe is disposed and the fallback MaybeSource subscribed to as a continuation.

Scheduler:

timeout does not operate by default on a particular Scheduler.

Type Parameters:

U - the value type of the

Parameters:

timeoutIndicator - the MaybeSource that indicates the timeout by signaling onSuccess or onComplete.

fallback - the MaybeSource that is subscribed to if the current Maybe times out

Returns:

the new Maybe instance

Throws:

NullPointerException - if timeoutIndicator or fallback is null

timeout

@BackpressureSupport(value=UNBOUNDED_IN)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<T> timeout(@NonNull Publisher<U> timeoutIndicator)

If the current Maybe source didn't signal an event before the timeoutIndicator Publisher signals, a TimeoutException is signaled instead.

Backpressure:

The timeoutIndicator Publisher is consumed in an unbounded manner and is cancelled after its first item.

Scheduler:

timeout does not operate by default on a particular Scheduler.

Type Parameters:

U - the value type of the

Parameters:

timeoutIndicator - the Publisher that indicates the timeout by signaling onSuccess or onComplete.

Returns:

the new Maybe instance

Throws:

NullPointerException - if timeoutIndicator is null

timeout

@BackpressureSupport(value=UNBOUNDED_IN)
 @CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U> @NonNull Maybe<T> timeout(@NonNull Publisher<U> timeoutIndicator,
        @NonNull MaybeSource<? extends T> fallback)

If the current Maybe didn't signal an event before the timeoutIndicator Publisher signals, the current Maybe is disposed and the fallback MaybeSource subscribed to as a continuation.

Backpressure:

The timeoutIndicator Publisher is consumed in an unbounded manner and is cancelled after its first item.

Scheduler:

timeout does not operate by default on a particular Scheduler.

Type Parameters:

U - the value type of the

Parameters:

timeoutIndicator - the MaybeSource that indicates the timeout by signaling onSuccess or onComplete

fallback - the MaybeSource that is subscribed to if the current Maybe times out

Returns:

the new Maybe instance

Throws:

NullPointerException - if timeoutIndicator or fallback is null

unsubscribeOn

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="custom")
public final @NonNull Maybe<T> unsubscribeOn(@NonNull Scheduler scheduler)

Returns a Maybe which makes sure when a MaybeObserver disposes the Disposable, that call is propagated up on the specified Scheduler.

Scheduler:

unsubscribeOn calls dispose() of the upstream on the Scheduler you specify.

Parameters:

scheduler - the target scheduler where to execute the disposal

Returns:

the new Maybe instance

Throws:

NullPointerException - if scheduler is null

zipWith

@CheckReturnValue
 @NonNull
 @SchedulerSupport(value="none")
public final <U,R> @NonNull Maybe<R> zipWith(@NonNull MaybeSource<? extends U> other,
        @NonNull BiFunction<? super T,? super U,? extends R> zipper)

Waits until this and the other MaybeSource signal a success value then applies the given BiFunction to those values and emits the BiFunction's resulting value to downstream.

If either this or the other MaybeSource is empty or signals an error, the resulting Maybe will terminate immediately and dispose the other source.

Scheduler:

zipWith does not operate by default on a particular Scheduler.

Type Parameters:

U - the type of items emitted by the other MaybeSource

R - the type of items emitted by the resulting Maybe

Parameters:

other - the other MaybeSource

zipper - a function that combines the pairs of items from the two MaybeSources to generate the items to be emitted by the resulting Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if other or zipper is null

See Also:

ReactiveX operators documentation: Zip

test

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull TestObserver<T> test()

Creates a TestObserver and subscribes it to this Maybe.

Scheduler:

test does not operate by default on a particular Scheduler.

Returns:

the new TestObserver instance

test

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull TestObserver<T> test(boolean dispose)

Creates a TestObserver optionally in cancelled state, then subscribes it to this Maybe.

Scheduler:

test does not operate by default on a particular Scheduler.

Parameters:

dispose - if true, the TestObserver will be disposed before subscribing to this Maybe.

Returns:

the new TestObserver instance

fromOptional

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Maybe<T> fromOptional(@NonNull Optional<T> optional)

Converts the existing value of the provided optional into a just(Object) or an empty optional into an empty() Maybe instance.

Note that the operator takes an already instantiated optional reference and does not by any means create this original optional. If the optional is to be created per consumer upon subscription, use defer(Supplier) around fromOptional:

 Maybe.defer(() -> Maybe.fromOptional(createOptional()));
 

Scheduler:

fromOptional does not operate by default on a particular Scheduler.

Type Parameters:

T - the element type of the optional value

Parameters:

optional - the optional value to convert into a Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if optional is null

Since:

3.0.0

See Also:

just(Object), empty()

fromCompletionStage

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public static <T> @NonNull Maybe<T> fromCompletionStage(@NonNull CompletionStage<T> stage)

Signals the completion value or error of the given (hot) CompletionStage-based asynchronous calculation.

Note that the operator takes an already instantiated, running or terminated CompletionStage. If the CompletionStage is to be created per consumer upon subscription, use defer(Supplier) around fromCompletionStage:

 Maybe.defer(() -> Maybe.fromCompletionStage(createCompletionStage()));
 

If the CompletionStage completes with null, the resulting Maybe is completed via onComplete.

Canceling the flow can't cancel the execution of the CompletionStage because CompletionStage itself doesn't support cancellation. Instead, the operator detaches from the CompletionStage.

Scheduler:

fromCompletionStage does not operate by default on a particular Scheduler.

Type Parameters:

T - the element type of the CompletionStage

Parameters:

stage - the CompletionStage to convert to Maybe and signal its terminal value or error

Returns:

the new Maybe instance

Throws:

NullPointerException - if stage is null

Since:

3.0.0

mapOptional

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final <R> @NonNull Maybe<R> mapOptional(@NonNull Function<? super T,Optional<? extends R>> mapper)

Maps the upstream success value into an Optional and emits the contained item if not empty.

Scheduler:

mapOptional does not operate by default on a particular Scheduler.

Type Parameters:

R - the non-null output type

Parameters:

mapper - the function that receives the upstream success item and should return a non-empty Optional to emit as the success output or an empty Optional to complete the Maybe

Returns:

the new Maybe instance

Throws:

NullPointerException - if mapper is null

Since:

3.0.0

See Also:

map(Function), filter(Predicate)

toCompletionStage

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull CompletionStage<T> toCompletionStage()

Signals the upstream success item (or a NoSuchElementException if the upstream is empty) via a CompletionStage.

The upstream can be canceled by converting the resulting CompletionStage into CompletableFuture via CompletionStage.toCompletableFuture() and calling CompletableFuture.cancel(boolean) on it. The upstream will be also cancelled if the resulting CompletionStage is converted to and completed manually by CompletableFuture.complete(Object) or CompletableFuture.completeExceptionally(Throwable).

CompletionStages don't have a notion of emptiness and allow nulls, therefore, one can either use toCompletionStage(Object) with null or turn the upstream into a sequence of Optionals and default to Optional.empty():

 CompletionStage<Optional<T>> stage = source.map(Optional::of).toCompletionStage(Optional.empty());
 

Scheduler:

toCompletionStage does not operate by default on a particular Scheduler.

Returns:

the new CompletionStage instance

Since:

3.0.0

See Also:

toCompletionStage(Object)

toCompletionStage

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final @NonNull CompletionStage<T> toCompletionStage(@Nullable T defaultItem)

Signals the upstream success item (or the default item if the upstream is empty) via a CompletionStage.

The upstream can be canceled by converting the resulting CompletionStage into CompletableFuture via CompletionStage.toCompletableFuture() and calling CompletableFuture.cancel(boolean) on it. The upstream will be also cancelled if the resulting CompletionStage is converted to and completed manually by CompletableFuture.complete(Object) or CompletableFuture.completeExceptionally(Throwable).

CompletionStages don't have a notion of emptiness and allow nulls, therefore, one can either use a defaultItem of null or turn the flow into a sequence of Optionals and default to Optional.empty():

 CompletionStage<Optional<T>> stage = source.map(Optional::of).toCompletionStage(Optional.empty());
 

Scheduler:

toCompletionStage does not operate by default on a particular Scheduler.

Parameters:

defaultItem - the item to signal if the upstream is empty

Returns:

the new CompletionStage instance

Since:

3.0.0

flattenStreamAsFlowable

@CheckReturnValue
 @SchedulerSupport(value="none")
 @BackpressureSupport(value=FULL)
 @NonNull
public final <R> @NonNull Flowable<R> flattenStreamAsFlowable(@NonNull Function<? super T,? extends Stream<? extends R>> mapper)

Maps the upstream succecss value into a Java Stream and emits its items to the downstream consumer as a Flowable.

The operator closes the Stream upon cancellation and when it terminates. The exceptions raised when closing a Stream are routed to the global error handler (RxJavaPlugins.onError(Throwable). If a Stream should not be closed, turn it into an Iterable and use flattenAsFlowable(Function):

 source.flattenAsFlowable(item -> createStream(item)::iterator);
 

Primitive streams are not supported and items have to be boxed manually (e.g., via IntStream.boxed()):

 source.flattenStreamAsFlowable(item -> IntStream.rangeClosed(1, 10).boxed());
 

Stream does not support concurrent usage so creating and/or consuming the same instance multiple times from multiple threads can lead to undefined behavior.

Backpressure:

The operator honors backpressure from downstream and iterates the given Stream on demand (i.e., when requested).

Scheduler:

flattenStreamAsFlowable does not operate by default on a particular Scheduler.

Type Parameters:

R - the element type of the Stream and the output Flowable

Parameters:

mapper - the function that receives the upstream success item and should return a Stream of values to emit.

Returns:

the new Flowable instance

Throws:

NullPointerException - if mapper is null

Since:

3.0.0

See Also:

flattenAsFlowable(Function), flattenStreamAsObservable(Function)

flattenStreamAsObservable

@CheckReturnValue
 @SchedulerSupport(value="none")
 @NonNull
public final <R> @NonNull Observable<R> flattenStreamAsObservable(@NonNull Function<? super T,? extends Stream<? extends R>> mapper)

Maps the upstream succecss value into a Java Stream and emits its items to the downstream consumer as an Observable.

The operator closes the Stream upon cancellation and when it terminates. The exceptions raised when closing a Stream are routed to the global error handler (RxJavaPlugins.onError(Throwable). If a Stream should not be closed, turn it into an Iterable and use flattenAsObservable(Function):

 source.flattenAsObservable(item -> createStream(item)::iterator);
 

Primitive streams are not supported and items have to be boxed manually (e.g., via IntStream.boxed()):

 source.flattenStreamAsObservable(item -> IntStream.rangeClosed(1, 10).boxed());
 

Stream does not support concurrent usage so creating and/or consuming the same instance multiple times from multiple threads can lead to undefined behavior.

Scheduler:

flattenStreamAsObservable does not operate by default on a particular Scheduler.

Type Parameters:

R - the element type of the Stream and the output Observable

Parameters:

mapper - the function that receives the upstream success item and should return a Stream of values to emit.

Returns:

the new Observable instance

Throws:

NullPointerException - if mapper is null

Since:

3.0.0

See Also:

flattenAsObservable(Function), flattenStreamAsFlowable(Function)