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A module that is everything required to understands Druid Segments

There is a newer version: 0.12.3

/*
 * Licensed to Metamarkets Group Inc. (Metamarkets) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Metamarkets 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 io.druid.segment;

import com.metamx.common.guava.ResourceClosingYielder;
import com.metamx.common.guava.Sequence;
import com.metamx.common.guava.Yielder;
import com.metamx.common.guava.YieldingAccumulator;
import com.metamx.common.guava.YieldingSequenceBase;

import java.io.Closeable;

/**
 */
public class ReferenceCountingSequence extends YieldingSequenceBase
{
  private final Sequence baseSequence;
  private final ReferenceCountingSegment segment;

  public ReferenceCountingSequence(Sequence baseSequence, ReferenceCountingSegment segment)
  {
    this.baseSequence = baseSequence;
    this.segment = segment;
  }

  @Override
  public  Yielder toYielder(
      OutType initValue, YieldingAccumulator accumulator
  )
  {
    final Closeable closeable = segment.increment();
    return new ResourceClosingYielder(baseSequence.toYielder(initValue, accumulator), closeable);
  }
}