content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.beam.runners.dataflow.worker;
  
  import com.google.api.client.json.GenericJson;
  import com.google.api.client.json.JsonFactory;
  import com.google.api.client.json.JsonGenerator;
  import java.io.IOException;
  import java.nio.charset.StandardCharsets;
  import org.apache.beam.sdk.extensions.gcp.util.Transport;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.io.ByteStreams;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.io.CountingOutputStream;
  
  /** A utility class for generic interactions with the Google Cloud Dataflow API. */
  public final class DataflowApiUtils {
    /**
     * Determines the serialized size (in bytes) of the {@link GenericJson} object that will be
     * serialized and sent to the Google Cloud Dataflow service API.
     *
     * <p>Uses only constant memory.
     */
    public static long computeSerializedSizeBytes(GenericJson object) throws IOException {
      JsonFactory factory = object.getFactory();
      if (factory == null) {
        factory = Transport.getJsonFactory();
      }
  
      CountingOutputStream stream = new CountingOutputStream(ByteStreams.nullOutputStream());
      JsonGenerator generator = null;
      try {
        generator = factory.createJsonGenerator(stream, StandardCharsets.UTF_8);
        generator.serialize(object);
        generator.close(); // also closes the stream.
      } finally {
        if (generator != null) {
          generator.close();
        }
      }
      return stream.getCount();
    }
  
    // Prevent construction of utility class.
    private DataflowApiUtils() {}
  }
  