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/*
 * Copyright (c) 2010-2015 Pivotal Software, Inc. All rights reserved.
 *
 * 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. See accompanying
 * LICENSE file.
 */

package com.gemstone.gemfire.distributed.internal;

import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.Collection;

/**
 * A LinkedBlockingQueue that supports stats.
 * Named OverflowQueue for historical reasons.
 * @author darrel
 *
 */
public class OverflowQueueWithDMStats extends LinkedBlockingQueue {
  private static final long serialVersionUID = -1846248853494394996L;
  protected final QueueStatHelper stats;
  
  /** Creates new OverflowQueueWithDMStats */
  public OverflowQueueWithDMStats(QueueStatHelper stats) {
    super();
    this.stats = stats;
  }
  /** Creates new OverflowQueueWithDMStats with a maximum capacity. */
  public OverflowQueueWithDMStats(int capacity, QueueStatHelper stats) {
    super(capacity);
    this.stats = stats;
  }
  
  @Override
  public boolean add(Object e) {
    preAdd(e);
    if (super.add(e)) {
      this.stats.add();
      return true;
    } else {
      postRemove(e);
      return false;
    }
  }
  @Override
  public boolean offer(Object e) {
    preAdd(e);
    if (super.offer(e)) {
      this.stats.add();
      return true;
    } else {
      postRemove(e);
      return false;
    }
  }
  @Override
  public void put(Object e) throws InterruptedException {
    if (Thread.interrupted()) throw new InterruptedException();
    preAddInterruptibly(e);
    boolean didOp = false;
    try {
      super.put(e);
      didOp = true;
      this.stats.add();
    } finally {
      if (!didOp) {
        postRemove(e);
      }
    }
  }
  @Override
  public boolean offer(Object e, long timeout, TimeUnit unit)
    throws InterruptedException {
    if (Thread.interrupted()) throw new InterruptedException();
    preAddInterruptibly(e);
    boolean didOp = false;
    try {
      if (super.offer(e, timeout, unit)) {
        didOp = true;
        this.stats.add();
        return true;
      } else {
        return false;
      }
    } finally {
      if (!didOp) {
        postRemove(e);
      }
    }
  }
  @Override
  public Object take() throws InterruptedException {
    if (Thread.interrupted()) throw new InterruptedException();
    Object result = super.take();
    postRemove(result);
    this.stats.remove();
    return result;
  }
  @Override
  public Object poll(long timeout, TimeUnit unit)
    throws InterruptedException {
    if (Thread.interrupted()) throw new InterruptedException();
    Object result = super.poll(timeout, unit);
    if (result != null) {
      postRemove(result);
      this.stats.remove();
    }
    return result;
  }
  @Override
  public boolean remove(Object o) {
    if (super.remove(o)) {
      this.stats.remove();
      postRemove(o);
      return true;
    } else {
      return false;
    }
  }
  @Override
  public int drainTo(Collection c) {
    int result = super.drainTo(c);
    if (result > 0) {
      this.stats.remove(result);
      postDrain(c);
    }
    return result;
  }
  @Override
  public int drainTo(Collection c, int maxElements) {
    int result = super.drainTo(c, maxElements);
    if (result > 0) {
      this.stats.remove(result);
      postDrain(c);
    }
    return result;
  }
  /**
   * Called before the specified object is added to this queue.
   */
  protected void preAddInterruptibly(Object o) throws InterruptedException {
    // do nothing in this class. sub-classes can override
  }
  /**
   * Called before the specified object is added to this queue.
   */
  protected void preAdd(Object o) {
    // do nothing in this class. sub-classes can override
  }
  /**
   * Called after the specified object is removed from this queue.
   */
  protected void postRemove(Object o) {
    // do nothing in this class. sub-classes can override
  }
  /**
   * Called after the specified collection of objects have been
   * drained (i.e. removed) from this queue.
   */
  protected void postDrain(Collection c) {
    // do nothing in this class. sub-classes can override
  }
}