docs(samples): add query with arrays parameters (#603)

Author: Praful Makani

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

@@ -0,0 +1,69 @@
+/*
+ * 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_query_params_arrays]
+import com.google.cloud.bigquery.BigQuery;
+import com.google.cloud.bigquery.BigQueryException;
+import com.google.cloud.bigquery.BigQueryOptions;
+import com.google.cloud.bigquery.QueryJobConfiguration;
+import com.google.cloud.bigquery.QueryParameterValue;
+import com.google.cloud.bigquery.TableResult;
+
+// Sample to running a query with array query parameters.
+public class QueryWithArrayParameters {
+
+  public static void runQueryWithArrayParameters() {
+    String gender = "M";
+    String[] states = {"WA", "WI", "WV", "WY"};
+    String query =
+        "SELECT name, sum(number) as count\n"
+            + "FROM `bigquery-public-data.usa_names.usa_1910_2013`\n"
+            + "WHERE gender = @gender\n"
+            + "AND state IN UNNEST(@states)\n"
+            + "GROUP BY name\n"
+            + "ORDER BY count DESC\n"
+            + "LIMIT 10;";
+    queryWithArrayParameters(query, gender, states);
+  }
+
+  public static void queryWithArrayParameters(String query, String gender, String[] states) {
+    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();
+
+      // Note: Standard SQL is required to use query parameters.
+      QueryJobConfiguration queryConfig =
+          QueryJobConfiguration.newBuilder(query)
+              .addNamedParameter("gender", QueryParameterValue.string(gender))
+              .addNamedParameter("states", QueryParameterValue.array(states, String.class))
+              .build();
+
+      TableResult results = bigquery.query(queryConfig);
+
+      // Print the results.
+      results
+          .iterateAll()
+          .forEach(row -> row.forEach(val -> System.out.printf("%s,", val.toString())));
+      System.out.println("Query with arrays parameters performed successfully");
+    } catch (BigQueryException | InterruptedException e) {
+      System.out.println("Query not performed \n" + e.toString());
+    }
+  }
+}
+// [END bigquery_query_params_arrays]

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

@@ -0,0 +1,59 @@
+/*
+ * 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 java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class QueryWithArrayParametersIT {
+
+  private ByteArrayOutputStream bout;
+  private PrintStream out;
+
+  @Before
+  public void setUp() {
+    bout = new ByteArrayOutputStream();
+    out = new PrintStream(bout);
+    System.setOut(out);
+  }
+
+  @After
+  public void tearDown() {
+    System.setOut(null);
+  }
+
+  @Test
+  public void testQueryWithArrayParameters() {
+    String gender = "M";
+    String[] states = {"WA", "WI", "WV", "WY"};
+    String query =
+        "SELECT name, sum(number) as count\n"
+            + "FROM `bigquery-public-data.usa_names.usa_1910_2013`\n"
+            + "WHERE gender = @gender\n"
+            + "AND state IN UNNEST(@states)\n"
+            + "GROUP BY name\n"
+            + "ORDER BY count DESC\n"
+            + "LIMIT 10;";
+    QueryWithArrayParameters.queryWithArrayParameters(query, gender, states);
+    assertThat(bout.toString()).contains("Query with arrays parameters performed successfully");
+  }
+}