docs(samples): add query with timestamp parameters (#604)

samples/snippets/src/main/java/com/example/bigquery/QueryWithTimestampParameters.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_params_timestamps]
+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;
+import org.threeten.bp.LocalDateTime;
+import org.threeten.bp.ZoneOffset;
+import org.threeten.bp.ZonedDateTime;
+
+// Sample to running a query with timestamp query parameters.
+public class QueryWithTimestampParameters {
+
+  public static void runQueryWithTimestampParameters() {
+    queryWithTimestampParameters();
+  }
+
+  public static void queryWithTimestampParameters() {
+    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();
+
+      ZonedDateTime timestamp = LocalDateTime.of(2016, 12, 7, 8, 0, 0).atZone(ZoneOffset.UTC);
+      String query = "SELECT TIMESTAMP_ADD(@ts_value, INTERVAL 1 HOUR);";
+      // Note: Standard SQL is required to use query parameters.
+      QueryJobConfiguration queryConfig =
+          QueryJobConfiguration.newBuilder(query)
+              .addNamedParameter(
+                  "ts_value",
+                  QueryParameterValue.timestamp(
+                      // Timestamp takes microseconds since 1970-01-01T00:00:00 UTC
+                      timestamp.toInstant().toEpochMilli() * 1000))
+              .build();
+
+      TableResult results = bigquery.query(queryConfig);
+
+      results
+          .iterateAll()
+          .forEach(row -> row.forEach(val -> System.out.printf("%s", val.toString())));
+
+      System.out.println("Query with timestamp parameter performed successfully.");
+    } catch (BigQueryException | InterruptedException e) {
+      System.out.println("Query not performed \n" + e.toString());
+    }
+  }
+}
+// [END bigquery_query_params_timestamps]

samples/snippets/src/test/java/com/example/bigquery/QueryWithTimestampParametersIT.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 QueryWithTimestampParametersIT {
+
+  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 testQueryWithTimestampParameters() {
+    QueryWithTimestampParameters.queryWithTimestampParameters();
+    assertThat(bout.toString()).contains("Query with timestamp parameter performed successfully.");
+  }
+}