/*
 * Copyright (C) 2010 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.ForwardingQueue;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Collection;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;

A BlockingQueue which forwards all its method calls to another BlockingQueue. Subclasses should override one or more methods to modify the behavior of the backing collection as desired per the decorator
pattern.
default method warning: This class does not forward calls to 
default methods. Instead, it inherits their default implementations. When those implementations invoke methods, they invoke methods on the ForwardingBlockingQueue. 
Author:
Raimundo Mirisola
Type parameters:
<E> – the type of elements held in this collection
Since:
4.0/**
 * A {@link BlockingQueue} which forwards all its method calls to another {@link BlockingQueue}.
 * Subclasses should override one or more methods to modify the behavior of the backing collection
 * as desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator
 * pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingBlockingQueue}.
 *
 * @author Raimundo Mirisola
 * @param <E> the type of elements held in this collection
 * @since 4.0
 */
@CanIgnoreReturnValue // TODO(cpovirk): Consider being more strict.
@GwtIncompatible
public abstract class ForwardingBlockingQueue<E> extends ForwardingQueue<E>
    implements BlockingQueue<E> {

  
Constructor for use by subclasses. /** Constructor for use by subclasses. */
  protected ForwardingBlockingQueue() {}

  @Override
  protected abstract BlockingQueue<E> delegate();

  @Override
  public int drainTo(Collection<? super E> c, int maxElements) {
    return delegate().drainTo(c, maxElements);
  }

  @Override
  public int drainTo(Collection<? super E> c) {
    return delegate().drainTo(c);
  }

  @Override
  public boolean offer(E e, long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().offer(e, timeout, unit);
  }

  @Override
  public E poll(long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().poll(timeout, unit);
  }

  @Override
  public void put(E e) throws InterruptedException {
    delegate().put(e);
  }

  @Override
  public int remainingCapacity() {
    return delegate().remainingCapacity();
  }

  @Override
  public E take() throws InterruptedException {
    return delegate().take();
  }
}