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.sdk.metrics;
  
  import java.io.Serializable;
  import java.util.Optional;
  import org.apache.beam.sdk.annotations.Internal;
  import org.apache.beam.sdk.util.HistogramData;
  
  /** Implementation of {@link Histogram} that delegates to the instance for the current context. */
  @Internal
  public class DelegatingHistogram implements Metric, Histogram, Serializable {
    private final MetricName name;
    private final HistogramData.BucketType bucketType;
    private final boolean processWideContainer;
  
    /**
     * @param name Metric name for this metric.
     * @param bucketType Histogram bucketing strategy.
     * @param processWideContainer Whether this Counter is stored in the ProcessWide container or the
     *     current thread's container.
     */
    public DelegatingHistogram(
        MetricName name, HistogramData.BucketType bucketType, boolean processWideContainer) {
      this.name = name;
      this.bucketType = bucketType;
      this.processWideContainer = processWideContainer;
    }
  
    private Optional<Histogram> getHistogram() {
      MetricsContainer container =
          processWideContainer
              ? MetricsEnvironment.getProcessWideContainer()
              : MetricsEnvironment.getCurrentContainer();
      if (container == null) {
        return Optional.empty();
      }
      return Optional.of(container.getHistogram(name, bucketType));
    }
  
    @Override
    public void update(double value) {
      getHistogram().ifPresent(histogram -> histogram.update(value));
    }
  
    @Override
    public void update(double... values) {
      getHistogram().ifPresent(histogram -> histogram.update(values));
    }
  
    @Override
    public MetricName getName() {
      return name;
    }
  }
  