XMLReader

See also:

• XMLFilter
• ParserAdapter
• XMLReaderAdapter

getContentHandler

public abstract ContentHandler getContentHandler ()

Return the current content handler.

getDTDHandler

public abstract DTDHandler getDTDHandler ()

Return the current DTD handler.

getEntityResolver

public abstract EntityResolver getEntityResolver ()

Return the current entity resolver.

getErrorHandler

public abstract ErrorHandler getErrorHandler ()

Return the current error handler.

getFeature

public abstract boolean getFeature (String name)

Look up the value of a feature flag.

The feature name is any fully-qualified URI. It is possible for an XMLReader to recognize a feature name but temporarily be unable to return its value. Some feature values may be available only in specific contexts, such as before, during, or after a parse. Also, some feature values may not be programmatically accessible. (In the case of an adapter for SAX1 Parser, there is no implementation-independent way to expose whether the underlying parser is performing validation, expanding external entities, and so forth.)

All XMLReaders are required to recognize the http://xml.org/sax/features/namespaces and the http://xml.org/sax/features/namespace-prefixes feature names.

Typical usage is something like this:

 XMLReader r = new MySAXDriver();

                         // try to activate validation
 try {
   r.setFeature("http://xml.org/sax/features/validation", true);
 } catch (SAXException e) {
   System.err.println("Cannot activate validation.");
 }

                         // register event handlers
 r.setContentHandler(new MyContentHandler());
 r.setErrorHandler(new MyErrorHandler());

                         // parse the first document
 try {
   r.parse("http://www.foo.com/mydoc.xml");
 } catch (IOException e) {
   System.err.println("I/O exception reading XML document");
 } catch (SAXException e) {
   System.err.println("XML exception reading document.");
 }
 

Implementors are free (and encouraged) to invent their own features, using names built on their own URIs.

getProperty

public abstract Object getProperty (String name)

Look up the value of a property.

The property name is any fully-qualified URI. It is possible for an XMLReader to recognize a property name but temporarily be unable to return its value. Some property values may be available only in specific contexts, such as before, during, or after a parse.

XMLReaders are not required to recognize any specific property names, though an initial core set is documented for SAX2.

Implementors are free (and encouraged) to invent their own properties, using names built on their own URIs.

parse

public abstract void parse (InputSource input)

Parse an XML document.

The application can use this method to instruct the XML reader to begin parsing an XML document from any valid input source (a character stream, a byte stream, or a URI).

Applications may not invoke this method while a parse is in progress (they should create a new XMLReader instead for each nested XML document). Once a parse is complete, an application may reuse the same XMLReader object, possibly with a different input source. Configuration of the XMLReader object (such as handler bindings and values established for feature flags and properties) is unchanged by completion of a parse, unless the definition of that aspect of the configuration explicitly specifies other behavior. (For example, feature flags or properties exposing characteristics of the document being parsed.)

During the parse, the XMLReader will provide information about the XML document through the registered event handlers.

This method is synchronous: it will not return until parsing has ended. If a client application wants to terminate parsing early, it should throw an exception.

parse

public abstract void parse (String systemId)

Parse an XML document from a system identifier (URI).

This method is a shortcut for the common case of reading a document from a system identifier. It is the exact equivalent of the following:

 parse(new InputSource(systemId));
 

If the system identifier is a URL, it must be fully resolved by the application before it is passed to the parser.

setContentHandler

public abstract void setContentHandler (ContentHandler handler)

Allow an application to register a content event handler.

If the application does not register a content handler, all content events reported by the SAX parser will be silently ignored.

Applications may register a new or different handler in the middle of a parse, and the SAX parser must begin using the new handler immediately.

setDTDHandler

public abstract void setDTDHandler (DTDHandler handler)

Allow an application to register a DTD event handler.

If the application does not register a DTD handler, all DTD events reported by the SAX parser will be silently ignored.

Applications may register a new or different handler in the middle of a parse, and the SAX parser must begin using the new handler immediately.

setEntityResolver

public abstract void setEntityResolver (EntityResolver resolver)

Allow an application to register an entity resolver.

If the application does not register an entity resolver, the XMLReader will perform its own default resolution.

Applications may register a new or different resolver in the middle of a parse, and the SAX parser must begin using the new resolver immediately.

setErrorHandler

public abstract void setErrorHandler (ErrorHandler handler)

Allow an application to register an error event handler.

If the application does not register an error handler, all error events reported by the SAX parser will be silently ignored; however, normal processing may not continue. It is highly recommended that all SAX applications implement an error handler to avoid unexpected bugs.

Applications may register a new or different handler in the middle of a parse, and the SAX parser must begin using the new handler immediately.

setFeature

public abstract void setFeature (String name, 
                boolean value)

Set the value of a feature flag.

The feature name is any fully-qualified URI. It is possible for an XMLReader to expose a feature value but to be unable to change the current value. Some feature values may be immutable or mutable only in specific contexts, such as before, during, or after a parse.

All XMLReaders are required to support setting http://xml.org/sax/features/namespaces to true and http://xml.org/sax/features/namespace-prefixes to false.

setProperty

public abstract void setProperty (String name, 
                Object value)

Set the value of a property.

The property name is any fully-qualified URI. It is possible for an XMLReader to recognize a property name but to be unable to change the current value. Some property values may be immutable or mutable only in specific contexts, such as before, during, or after a parse.

XMLReaders are not required to recognize setting any specific property names, though a core set is defined by SAX2.

This method is also the standard mechanism for setting extended handlers.