1/*
2 * Copyright (C) 2010 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.util.concurrent;
18
19import com.google.common.collect.ForwardingQueue;
20
21import java.util.Collection;
22import java.util.concurrent.BlockingQueue;
23import java.util.concurrent.TimeUnit;
24
25/**
26 * A {@link BlockingQueue} which forwards all its method calls to another
27 * {@link BlockingQueue}. Subclasses should override one or more methods to
28 * modify the behavior of the backing collection as desired per the <a
29 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
30 *
31 * @author Raimundo Mirisola
32 *
33 * @param <E> the type of elements held in this collection
34 * @since 4.0
35 */
36public abstract class ForwardingBlockingQueue<E> extends ForwardingQueue<E>
37    implements BlockingQueue<E> {
38
39  /** Constructor for use by subclasses. */
40  protected ForwardingBlockingQueue() {}
41
42  @Override protected abstract BlockingQueue<E> delegate();
43
44  @Override public int drainTo(
45      Collection<? super E> c, int maxElements) {
46    return delegate().drainTo(c, maxElements);
47  }
48
49  @Override public int drainTo(Collection<? super E> c) {
50    return delegate().drainTo(c);
51  }
52
53  @Override public boolean offer(E e, long timeout, TimeUnit unit)
54      throws InterruptedException {
55    return delegate().offer(e, timeout, unit);
56  }
57
58  @Override public E poll(long timeout, TimeUnit unit)
59      throws InterruptedException {
60    return delegate().poll(timeout, unit);
61  }
62
63  @Override public void put(E e) throws InterruptedException {
64    delegate().put(e);
65  }
66
67  @Override public int remainingCapacity() {
68    return delegate().remainingCapacity();
69  }
70
71  @Override public E take() throws InterruptedException {
72    return delegate().take();
73  }
74}
75