docs(samples): add update model description (#617)

Author: Praful Makani

samples/snippets/src/main/java/com/example/bigquery/UpdateModelDescription.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.bigquery;
+
+// [START bigquery_update_model_description]
+import com.google.cloud.bigquery.BigQuery;
+import com.google.cloud.bigquery.BigQueryException;
+import com.google.cloud.bigquery.BigQueryOptions;
+import com.google.cloud.bigquery.Model;
+import com.google.cloud.bigquery.ModelId;
+
+// Sample to update description on a model
+public class UpdateModelDescription {
+
+  public static void runUpdateModelDescription() {
+    // TODO(developer): Replace these variables before running the sample.
+    String datasetName = "MY_DATASET_NAME";
+    String modelName = "MY_MODEL_NAME";
+    String newDescription = "A really great model.";
+    updateModelDescription(datasetName, modelName, newDescription);
+  }
+
+  public static void updateModelDescription(
+      String datasetName, String modelName, String newDescription) {
+    try {
+      // Initialize client that will be used to send requests. This client only needs to be created
+      // once, and can be reused for multiple requests.
+      BigQuery bigquery = BigQueryOptions.getDefaultInstance().getService();
+
+      Model model = bigquery.getModel(ModelId.of(datasetName, modelName));
+      bigquery.update(model.toBuilder().setDescription(newDescription).build());
+      System.out.println("Model description updated successfully to " + newDescription);
+    } catch (BigQueryException e) {
+      System.out.println("Model description was not updated \n" + e.toString());
+    }
+  }
+}
+// [END bigquery_update_model_description]

samples/snippets/src/test/java/com/example/bigquery/UpdateModelDescriptionIT.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.bigquery;
+
+import static com.google.common.truth.Truth.assertThat;
+import static junit.framework.TestCase.assertNotNull;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.util.UUID;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class UpdateModelDescriptionIT {
+
+  private String modelName;
+  private ByteArrayOutputStream bout;
+  private PrintStream out;
+
+  private static final String BIGQUERY_DATASET_NAME = requireEnvVar("BIGQUERY_DATASET_NAME");
+
+  private static String requireEnvVar(String varName) {
+    String value = System.getenv(varName);
+    assertNotNull(
+        "Environment variable " + varName + " is required to perform these tests.",
+        System.getenv(varName));
+    return value;
+  }
+
+  @BeforeClass
+  public static void checkRequirements() {
+    requireEnvVar("BIGQUERY_DATASET_NAME");
+  }
+
+  @Before
+  public void setUp() {
+    bout = new ByteArrayOutputStream();
+    out = new PrintStream(bout);
+    System.setOut(out);
+    // create a test model
+    modelName = "MY_MODEL_NAME_TEST_" + UUID.randomUUID().toString().substring(0, 8);
+    String sql =
+        "CREATE MODEL `"
+            + BIGQUERY_DATASET_NAME
+            + "."
+            + modelName
+            + "`"
+            + "OPTIONS ( "
+            + "model_type='linear_reg', "
+            + "max_iteration=1, "
+            + "learn_rate=0.4, "
+            + "learn_rate_strategy='constant' "
+            + ") AS ( "
+            + "	SELECT 'a' AS f1, 2.0 AS label "
+            + "UNION ALL "
+            + "SELECT 'b' AS f1, 3.8 AS label "
+            + ")";
+    CreateModel.createModel(sql);
+
+    bout = new ByteArrayOutputStream();
+    out = new PrintStream(bout);
+    System.setOut(out);
+  }
+
+  @After
+  public void tearDown() {
+    // Clean up
+    DeleteModel.deleteModel(BIGQUERY_DATASET_NAME, modelName);
+    System.setOut(null);
+  }
+
+  @Test
+  public void testUpdateModelDescription() {
+    String newDescription = "A really great model.";
+    UpdateModelDescription.updateModelDescription(BIGQUERY_DATASET_NAME, modelName, newDescription);
+    assertThat(bout.toString()).contains("Model description updated successfully");
+  }
+}