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.flink.metrics;
  
  import org.apache.beam.runners.core.metrics.MetricsContainerStepMap;
  import org.apache.flink.api.common.accumulators.Accumulator;
  import org.apache.flink.api.common.accumulators.SimpleAccumulator;
  
  /**
   * Accumulator of {@link MetricsContainerStepMap}. This accumulator will only be reported to Flink
   * when the job ends. This avoids the runtime overhead for accumulators which are continously sent
   * to the job manager.
   */
  public class MetricsAccumulator implements SimpleAccumulator<MetricsContainerStepMap> {
  
    private MetricsContainerStepMap metricsContainers = new MetricsContainerStepMap();
  
    @Override
    public void add(MetricsContainerStepMap value) {
      metricsContainers.updateAll(value);
    }
  
    @Override
    public MetricsContainerStepMap getLocalValue() {
      return metricsContainers;
    }
  
    @Override
    public void resetLocal() {
      this.metricsContainers = new MetricsContainerStepMap();
    }
  
    @Override
    public void merge(Accumulator<MetricsContainerStepMap, MetricsContainerStepMap> other) {
      this.add(other.getLocalValue());
    }
  
    @Override
    @SuppressWarnings("ReturnValueIgnored")
    public Accumulator<MetricsContainerStepMap, MetricsContainerStepMap> clone() {
      try {
        super.clone();
      } catch (CloneNotSupportedException ignored) {
      }
      MetricsAccumulator metricsAccumulator = new MetricsAccumulator();
      metricsAccumulator.getLocalValue().updateAll(this.getLocalValue());
      return metricsAccumulator;
    }
  }
  