text: /*
   * Copyright 2020, OpenTelemetry Authors
   *
   * Licensed 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 io.opentelemetry.sdk.metrics.aggregator;
  
  import io.opentelemetry.common.Labels;
  import io.opentelemetry.sdk.metrics.data.MetricData.LongPoint;
  import io.opentelemetry.sdk.metrics.data.MetricData.Point;
  import java.util.concurrent.atomic.AtomicLong;
  
  public final class LongSumAggregator extends AbstractAggregator {
  
    private static final long DEFAULT_VALUE = 0L;
    private static final AggregatorFactory AGGREGATOR_FACTORY =
        new AggregatorFactory() {
          @Override
          public Aggregator getAggregator() {
            return new LongSumAggregator();
          }
        };
  
    // TODO: Change to use LongAdder when changed to java8.
    private final AtomicLong current = new AtomicLong(DEFAULT_VALUE);
  
    /**
     * Returns an {@link AggregatorFactory} that produces {@link LongSumAggregator} instances.
     *
     * @return an {@link AggregatorFactory} that produces {@link LongSumAggregator} instances.
     */
    public static AggregatorFactory getFactory() {
      return AGGREGATOR_FACTORY;
    }
  
    @Override
    void doMergeAndReset(Aggregator aggregator) {
      LongSumAggregator other = (LongSumAggregator) aggregator;
      other.current.getAndAdd(this.current.getAndSet(DEFAULT_VALUE));
    }
  
    @Override
    public Point toPoint(long startEpochNanos, long epochNanos, Labels labels) {
      return LongPoint.create(startEpochNanos, epochNanos, labels, current.get());
    }
  
    @Override
    public void doRecordLong(long value) {
      current.getAndAdd(value);
    }
  }
  