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 org.apache.beam.runners.core.ElementByteSizeObservable;
  import org.apache.beam.runners.dataflow.worker.counters.Counter;
  import org.apache.beam.runners.dataflow.worker.counters.CounterFactory;
  import org.apache.beam.runners.dataflow.worker.counters.CounterName;
  import org.apache.beam.runners.dataflow.worker.counters.NameContext;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.ElementCounter;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.OutputObjectAndByteCounter;
  import org.apache.beam.sdk.values.WindowedValue;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.annotations.VisibleForTesting;
  
  /**
   * A Dataflow-specific version of {@link ElementCounter}. It counts element windows as ElementCount.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class DataflowOutputCounter implements ElementCounter {
    /** Number of logical element and single window pairs that were processed. */
    private static final String ELEMENT_COUNTER_NAME = "-ElementCount";
  
    private static final String MEAN_BYTE_COUNTER_NAME = "-MeanByteCount";
  
    private OutputObjectAndByteCounter objectAndByteCounter;
    private Counter<Long, ?> elementCount;
  
    public DataflowOutputCounter(
        String outputName, CounterFactory counterFactory, NameContext nameContext) {
      this(outputName, null, counterFactory, nameContext);
    }
  
    public DataflowOutputCounter(
        String outputName,
        ElementByteSizeObservable<?> elementByteSizeObservable,
        CounterFactory counterFactory,
        NameContext nameContext) {
      objectAndByteCounter =
          new OutputObjectAndByteCounter(elementByteSizeObservable, counterFactory, nameContext);
      objectAndByteCounter.countMeanByte(outputName + MEAN_BYTE_COUNTER_NAME);
      createElementCounter(counterFactory, outputName + ELEMENT_COUNTER_NAME);
    }
  
    @Override
    public void update(Object elem) throws Exception {
      objectAndByteCounter.update(elem);
      long windowsSize = ((WindowedValue<?>) elem).getWindows().size();
      if (windowsSize == 0) {
        // GroupingShuffleReader produces ValueInEmptyWindows.
        // For now, we count the element at least once to keep the current counter
        // behavior.
        elementCount.addValue(1L);
      } else {
        elementCount.addValue(windowsSize);
      }
    }
  
    @Override
    public void finishLazyUpdate(Object elem) {
      objectAndByteCounter.finishLazyUpdate(elem);
    }
  
    @VisibleForTesting
    static String getElementCounterName(String prefix) {
      return prefix + ELEMENT_COUNTER_NAME;
    }
  
    @VisibleForTesting
    static String getMeanByteCounterName(String prefix) {
      return prefix + MEAN_BYTE_COUNTER_NAME;
    }
  
    private void createElementCounter(CounterFactory factory, String name) {
      // TODO: use the name context to name the counter
      elementCount = factory.longSum(CounterName.named(name));
    }
  }
  