001/*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.util.concurrent;
016
017import com.google.common.annotations.GwtIncompatible;
018import com.google.errorprone.annotations.CanIgnoreReturnValue;
019import java.util.concurrent.Callable;
020import org.checkerframework.checker.nullness.qual.Nullable;
021
022/**
023 * A listening executor service which forwards all its method calls to another listening executor
024 * service. Subclasses should override one or more methods to modify the behavior of the backing
025 * executor service as desired per the <a
026 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
027 *
028 * @author Isaac Shum
029 * @since 10.0
030 */
031@CanIgnoreReturnValue // TODO(cpovirk): Consider being more strict.
032@GwtIncompatible
033@ElementTypesAreNonnullByDefault
034public abstract class ForwardingListeningExecutorService extends ForwardingExecutorService
035    implements ListeningExecutorService {
036  /** Constructor for use by subclasses. */
037  protected ForwardingListeningExecutorService() {}
038
039  @Override
040  protected abstract ListeningExecutorService delegate();
041
042  @Override
043  public <T extends @Nullable Object> ListenableFuture<T> submit(Callable<T> task) {
044    return delegate().submit(task);
045  }
046
047  @Override
048  public ListenableFuture<?> submit(Runnable task) {
049    return delegate().submit(task);
050  }
051
052  @Override
053  public <T extends @Nullable Object> ListenableFuture<T> submit(
054      Runnable task, @ParametricNullness T result) {
055    return delegate().submit(task, result);
056  }
057}