docs(samples): add query script (#605)

Author: Praful Makani

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

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+/*
+ * 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_script]
+import com.google.api.gax.paging.Page;
+import com.google.cloud.bigquery.BigQuery;
+import com.google.cloud.bigquery.BigQueryException;
+import com.google.cloud.bigquery.BigQueryOptions;
+import com.google.cloud.bigquery.Job;
+import com.google.cloud.bigquery.JobInfo;
+import com.google.cloud.bigquery.QueryJobConfiguration;
+
+// Sample to run query script.
+public class QueryScript {
+
+  public static void runQueryScript() {
+    String script =
+        "-- Declare a variable to hold names as an array.\n"
+            + "DECLARE top_names ARRAY<STRING>;\n"
+            + "-- Build an array of the top 100 names from the year 2017.\n"
+            + "SET top_names = (\n"
+            + "  SELECT ARRAY_AGG(name ORDER BY number DESC LIMIT 100)\n"
+            + "  FROM `bigquery-public-data`.usa_names.usa_1910_current\n"
+            + "  WHERE year = 2017\n"
+            + ");\n"
+            + "-- Which names appear as words in Shakespeare's plays?\n"
+            + "SELECT\n"
+            + "  name AS shakespeare_name\n"
+            + "FROM UNNEST(top_names) AS name\n"
+            + "WHERE name IN (\n"
+            + "  SELECT word\n"
+            + "  FROM `bigquery-public-data`.samples.shakespeare\n"
+            + ");";
+    queryScript(script);
+  }
+
+  public static void queryScript(String script) {
+    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();
+
+      QueryJobConfiguration queryConfig = QueryJobConfiguration.newBuilder(script).build();
+      Job createJob = bigquery.create(JobInfo.of(queryConfig));
+      // Wait for the whole script to finish.
+      JobInfo jobInfo = createJob.waitFor();
+      String parentJobId = jobInfo.getJobId().getJob();
+
+      // Fetch jobs created by the SQL script.
+      Page<Job> childJobs = bigquery.listJobs(BigQuery.JobListOption.parentJobId(parentJobId));
+      childJobs
+          .iterateAll()
+          .forEach(job -> System.out.printf("Child Job Id: ", job.getJobId().getJob()));
+
+      System.out.println("Query script performed successfully.");
+    } catch (BigQueryException | InterruptedException e) {
+      System.out.println("Query not performed \n" + e.toString());
+    }
+  }
+}
+// [END bigquery_query_script]

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

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+/*
+ * 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 QueryScriptIT {
+
+  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 testQueryScript() {
+    String script =
+        "-- Declare a variable to hold names as an array.\n"
+            + "DECLARE top_names ARRAY<STRING>;\n"
+            + "-- Build an array of the top 100 names from the year 2017.\n"
+            + "SET top_names = (\n"
+            + "  SELECT ARRAY_AGG(name ORDER BY number DESC LIMIT 100)\n"
+            + "  FROM `bigquery-public-data`.usa_names.usa_1910_current\n"
+            + "  WHERE year = 2017\n"
+            + ");\n"
+            + "-- Which names appear as words in Shakespeare's plays?\n"
+            + "SELECT\n"
+            + "  name AS shakespeare_name\n"
+            + "FROM UNNEST(top_names) AS name\n"
+            + "WHERE name IN (\n"
+            + "  SELECT word\n"
+            + "  FROM `bigquery-public-data`.samples.shakespeare\n"
+            + ");";
+
+    QueryScript.queryScript(script);
+    assertThat(bout.toString()).contains("Query script performed successfully.");
+  }
+}