001/*
002 * Copyright (C) 2010 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.util.concurrent;
018
019import com.google.common.collect.ForwardingQueue;
020
021import java.util.Collection;
022import java.util.concurrent.BlockingQueue;
023import java.util.concurrent.TimeUnit;
024
025/**
026 * A {@link BlockingQueue} which forwards all its method calls to another
027 * {@link BlockingQueue}. Subclasses should override one or more methods to
028 * modify the behavior of the backing collection as desired per the <a
029 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
030 *
031 * @author Raimundo Mirisola
032 *
033 * @param <E> the type of elements held in this collection
034 * @since 4.0
035 */
036public abstract class ForwardingBlockingQueue<E> extends ForwardingQueue<E>
037    implements BlockingQueue<E> {
038
039  /** Constructor for use by subclasses. */
040  protected ForwardingBlockingQueue() {}
041
042  @Override protected abstract BlockingQueue<E> delegate();
043
044  @Override public int drainTo(
045      Collection<? super E> c, int maxElements) {
046    return delegate().drainTo(c, maxElements);
047  }
048
049  @Override public int drainTo(Collection<? super E> c) {
050    return delegate().drainTo(c);
051  }
052
053  @Override public boolean offer(E e, long timeout, TimeUnit unit)
054      throws InterruptedException {
055    return delegate().offer(e, timeout, unit);
056  }
057
058  @Override public E poll(long timeout, TimeUnit unit)
059      throws InterruptedException {
060    return delegate().poll(timeout, unit);
061  }
062
063  @Override public void put(E e) throws InterruptedException {
064    delegate().put(e);
065  }
066
067  @Override public int remainingCapacity() {
068    return delegate().remainingCapacity();
069  }
070
071  @Override public E take() throws InterruptedException {
072    return delegate().take();
073  }
074}