1/*
2 * Copyright (C) 2012 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.collect;
18
19import java.util.Collection;
20import java.util.concurrent.BlockingDeque;
21import java.util.concurrent.TimeUnit;
22
23/**
24 * A {@link BlockingDeque} which forwards all its method calls to another {@code BlockingDeque}.
25 * Subclasses should override one or more methods to modify the behavior of the backing deque as
26 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
27 *
28 * <p><b>Warning:</b> The methods of {@code ForwardingBlockingDeque} forward
29 * <b>indiscriminately</b> to the methods of the delegate. For example, overriding {@link #add}
30 * alone <b>will not</b> change the behaviour of {@link #offer} which can lead to unexpected
31 * behaviour. In this case, you should override {@code offer} as well, either providing your own
32 * implementation, or delegating to the provided {@code standardOffer} method.
33 *
34 * <p>
35 * The {@code standard} methods are not guaranteed to be thread-safe, even when all of the methods
36 * that they depend on are thread-safe.
37 *
38 * @author Emily Soldal
39 * @since 14.0
40 */
41public abstract class ForwardingBlockingDeque<E>
42    extends ForwardingDeque<E> implements BlockingDeque<E> {
43
44  /** Constructor for use by subclasses. */
45  protected ForwardingBlockingDeque() {}
46
47  @Override protected abstract BlockingDeque<E> delegate();
48
49  @Override
50  public int remainingCapacity() {
51    return delegate().remainingCapacity();
52  }
53
54  @Override
55  public void putFirst(E e) throws InterruptedException {
56    delegate().putFirst(e);
57  }
58
59  @Override
60  public void putLast(E e) throws InterruptedException {
61    delegate().putLast(e);
62  }
63
64  @Override
65  public boolean offerFirst(E e, long timeout, TimeUnit unit) throws InterruptedException {
66    return delegate().offerFirst(e, timeout, unit);
67  }
68
69  @Override
70  public boolean offerLast(E e, long timeout, TimeUnit unit) throws InterruptedException {
71    return delegate().offerLast(e, timeout, unit);
72  }
73
74  @Override
75  public E takeFirst() throws InterruptedException {
76    return delegate().takeFirst();
77  }
78
79  @Override
80  public E takeLast() throws InterruptedException {
81    return delegate().takeLast();
82  }
83
84  @Override
85  public E pollFirst(long timeout, TimeUnit unit) throws InterruptedException {
86    return delegate().pollFirst(timeout, unit);
87  }
88
89  @Override
90  public E pollLast(long timeout, TimeUnit unit) throws InterruptedException {
91    return delegate().pollLast(timeout, unit);
92  }
93
94  @Override
95  public void put(E e) throws InterruptedException {
96    delegate().put(e);
97  }
98
99  @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}
124