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.util.common.worker;
  
  import java.io.Closeable;
  import org.apache.beam.runners.dataflow.worker.counters.Counter;
  import org.apache.beam.runners.dataflow.worker.counters.CounterName;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.MoreObjects;
  
  /** A write operation. */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class WriteOperation extends ReceivingOperation {
    /** The Sink this operation writes to. */
    public final Sink<?> sink;
  
    /** Invalid sink index for reportSinkIndexIfEmptyOutput(). */
    protected static final int INVALID_SINK_INDEX = -1;
  
    /** The total byte counter for all data written by this operation. */
    final Counter<Long, Long> byteCount;
  
    /** The Sink's writer this operation writes to, created by start(). */
    Sink.SinkWriter<Object> writer;
  
    protected WriteOperation(
        Sink<?> sink,
        OutputReceiver[] receivers,
        OperationContext context,
        CounterName bytesCounterName) {
      super(receivers, context);
      this.sink = sink;
      this.byteCount = context.counterFactory().longSum(bytesCounterName);
    }
  
    private static CounterName bytesCounterName(OperationContext context) {
      return CounterName.named(context.nameContext().systemName() + "-ByteCount");
    }
  
    public static WriteOperation create(
        Sink<?> sink, OutputReceiver[] receivers, OperationContext context) {
      return new WriteOperation(sink, receivers, context, bytesCounterName(context));
    }
  
    public static WriteOperation forTest(Sink<?> sink, OperationContext context) {
      return create(sink, new OutputReceiver[] {}, context);
    }
  
    public Sink<?> getSink() {
      return sink;
    }
  
    @SuppressWarnings("unchecked")
    protected void initializeWriter() throws Exception {
      writer = (Sink.SinkWriter<Object>) sink.writer();
    }
  
    @Override
    public void start() throws Exception {
      try (Closeable scope = context.enterStart()) {
        super.start();
        initializeWriter();
      }
    }
  
    protected void mayInitializeWriterInProcess() throws Exception {}
  
    @Override
    public void process(Object outputElem) throws Exception {
      try (Closeable scope = context.enterProcess()) {
        checkStarted();
        mayInitializeWriterInProcess();
        byteCount.addValue(writer.add(outputElem));
      }
    }
  
    @Override
    public void finish() throws Exception {
      try (Closeable scope = context.enterFinish()) {
        checkStarted();
        try {
          if (writer != null) {
            writer.close();
          }
        } finally {
          super.finish();
          writer = null;
        }
      }
    }
  
    @Override
    public void abort() throws Exception {
      if (writer == null) {
        // If we haven't started, or have already closed the writer, we cannot abort it.
        super.abort();
        return;
      }
  
      try (Closeable scope = context.enterAbort()) {
        writer.abort();
      } finally {
        super.abort();
        writer = null;
      }
    }
  
    @Override
    public boolean supportsRestart() {
      return sink.supportsRestart();
    }
  
    public Counter<Long, Long> getByteCount() {
      return byteCount;
    }
  
    /**
     * Reports the sink index of a WriteOperation if the WriteOperation did not produce any output.
     * Returns INVALID_SINK_INDEX for a WriteOperation that produced output. NOTE: this is only used
     * by FlumeWriteOperation. TODO: Report system_name instead of sink_index when enabling this
     * feature on Dataflow.
     */
    public int reportSinkIndexIfEmptyOutput() {
      return INVALID_SINK_INDEX;
    }
  
    @Override
    public String toString() {
      return MoreObjects.toStringHelper(this)
          .add("sink", sink)
          .add("writer", writer)
          .add("byteCount", byteCount)
          .toString();
    }
  }
  