    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
    017    package com.google.common.util.concurrent;
    018
    019    import com.google.common.collect.ForwardingQueue;
    020
    021    import java.util.Collection;
    022    import java.util.concurrent.BlockingQueue;
    023    import 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     */
    036    public 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    }