001/*
002 * Copyright (C) 2012 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.collect;
018
019import java.util.Collection;
020import java.util.concurrent.BlockingDeque;
021import java.util.concurrent.TimeUnit;
022
023/**
024 * A {@link BlockingDeque} which forwards all its method calls to another {@code BlockingDeque}.
025 * Subclasses should override one or more methods to modify the behavior of the backing deque as
026 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
027 *
028 * <p><b>Warning:</b> The methods of {@code ForwardingBlockingDeque} forward
029 * <b>indiscriminately</b> to the methods of the delegate. For example, overriding {@link #add}
030 * alone <b>will not</b> change the behaviour of {@link #offer} which can lead to unexpected
031 * behaviour. In this case, you should override {@code offer} as well, either providing your own
032 * implementation, or delegating to the provided {@code standardOffer} method.
033 *
034 * <p>
035 * The {@code standard} methods are not guaranteed to be thread-safe, even when all of the methods
036 * that they depend on are thread-safe.
037 *
038 * @author Emily Soldal
039 * @since 14.0
040 */
041public abstract class ForwardingBlockingDeque<E>
042    extends ForwardingDeque<E> implements BlockingDeque<E> {
043
044  /** Constructor for use by subclasses. */
045  protected ForwardingBlockingDeque() {}
046
047  @Override protected abstract BlockingDeque<E> delegate();
048
049  @Override
050  public int remainingCapacity() {
051    return delegate().remainingCapacity();
052  }
053
054  @Override
055  public void putFirst(E e) throws InterruptedException {
056    delegate().putFirst(e);
057  }
058
059  @Override
060  public void putLast(E e) throws InterruptedException {
061    delegate().putLast(e);
062  }
063
064  @Override
065  public boolean offerFirst(E e, long timeout, TimeUnit unit) throws InterruptedException {
066    return delegate().offerFirst(e, timeout, unit);
067  }
068
069  @Override
070  public boolean offerLast(E e, long timeout, TimeUnit unit) throws InterruptedException {
071    return delegate().offerLast(e, timeout, unit);
072  }
073
074  @Override
075  public E takeFirst() throws InterruptedException {
076    return delegate().takeFirst();
077  }
078
079  @Override
080  public E takeLast() throws InterruptedException {
081    return delegate().takeLast();
082  }
083
084  @Override
085  public E pollFirst(long timeout, TimeUnit unit) throws InterruptedException {
086    return delegate().pollFirst(timeout, unit);
087  }
088
089  @Override
090  public E pollLast(long timeout, TimeUnit unit) throws InterruptedException {
091    return delegate().pollLast(timeout, unit);
092  }
093
094  @Override
095  public void put(E e) throws InterruptedException {
096    delegate().put(e);
097  }
098
099  @Override
100  public boolean offer(E e, long timeout, TimeUnit unit) throws InterruptedException {
101    return delegate().offer(e, timeout, unit);
102  }
103
104  @Override
105  public E take() throws InterruptedException {
106    return delegate().take();
107  }
108
109  @Override
110  public E poll(long timeout, TimeUnit unit) throws InterruptedException {
111    return delegate().poll(timeout, unit);
112  }
113
114  @Override
115  public int drainTo(Collection<? super E> c) {
116    return delegate().drainTo(c);
117  }
118
119  @Override
120  public int drainTo(Collection<? super E> c, int maxElements) {
121    return delegate().drainTo(c, maxElements);
122  }
123}