001/*
002 * Copyright (C) 2009 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
017package com.google.common.util.concurrent;
018
019import com.google.common.annotations.Beta;
020import com.google.common.base.Throwables;
021import com.google.common.collect.ForwardingObject;
022
023import java.util.concurrent.ExecutionException;
024
025/**
026 * A {@link Service} that forwards all method calls to another service.
027 *
028 * @author Chris Nokleberg
029 * @since 1
030 */
031@Beta
032public abstract class ForwardingService extends ForwardingObject
033    implements Service {
034
035  /** Constructor for use by subclasses. */
036  protected ForwardingService() {}
037
038  @Override protected abstract Service delegate();
039
040  @Override public ListenableFuture<State> start() {
041    return delegate().start();
042  }
043
044  @Override public State state() {
045    return delegate().state();
046  }
047
048  @Override public ListenableFuture<State> stop() {
049    return delegate().stop();
050  }
051
052  @Override public State startAndWait() {
053    return delegate().startAndWait();
054  }
055
056  @Override public State stopAndWait() {
057    return delegate().stopAndWait();
058  }
059
060  @Override public boolean isRunning() {
061    return delegate().isRunning();
062  }
063
064  /**
065   * A sensible default implementation of {@link #startAndWait()}, in terms of
066   * {@link #start}. If you override {@link #start}, you may wish to override
067   * {@link #startAndWait()} to forward to this implementation.
068   * @since 9
069   */
070  protected State standardStartAndWait() {
071    try {
072      return Futures.makeUninterruptible(start()).get();
073    } catch (ExecutionException e) {
074      throw Throwables.propagate(e.getCause());
075    }
076  }
077
078  /**
079   * A sensible default implementation of {@link #stopAndWait()}, in terms of
080   * {@link #stop}. If you override {@link #stop}, you may wish to override
081   * {@link #stopAndWait()} to forward to this implementation.
082   * @since 9
083   */
084  protected State standardStopAndWait() {
085    try {
086      return Futures.makeUninterruptible(stop()).get();
087    } catch (ExecutionException e) {
088      throw Throwables.propagate(e.getCause());
089    }
090  }
091}