001/*
002 * Copyright (C) 2010 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.Collection;
020import java.util.List;
021import java.util.concurrent.Callable;
022import java.util.concurrent.ExecutorService;
023import java.util.concurrent.Future;
024import java.util.concurrent.RejectedExecutionException;
025import java.util.concurrent.TimeUnit;
026
027/**
028 * An {@link ExecutorService} that returns {@link ListenableFuture} instances. To create an instance
029 * from an existing {@link ExecutorService}, call {@link
030 * MoreExecutors#listeningDecorator(ExecutorService)}.
031 *
032 * @author Chris Povirk
033 * @since 10.0
034 */
035@CanIgnoreReturnValue
036@GwtIncompatible
037public interface ListeningExecutorService extends ExecutorService {
038  /**
039   * @return a {@code ListenableFuture} representing pending completion of the task
040   * @throws RejectedExecutionException {@inheritDoc}
041   */
042  @Override
043  <T> ListenableFuture<T> submit(Callable<T> task);
044
045  /**
046   * @return a {@code ListenableFuture} representing pending completion of the task
047   * @throws RejectedExecutionException {@inheritDoc}
048   */
049  @Override
050  ListenableFuture<?> submit(Runnable task);
051
052  /**
053   * @return a {@code ListenableFuture} representing pending completion of the task
054   * @throws RejectedExecutionException {@inheritDoc}
055   */
056  @Override
057  <T> ListenableFuture<T> submit(Runnable task, T result);
058
059  /**
060   * {@inheritDoc}
061   *
062   * <p>All elements in the returned list must be {@link ListenableFuture} instances. The easiest
063   * way to obtain a {@code List<ListenableFuture<T>>} from this method is an unchecked (but safe)
064   * cast:<pre>
065   *   {@code @SuppressWarnings("unchecked") // guaranteed by invokeAll contract}
066   *   {@code List<ListenableFuture<T>> futures = (List) executor.invokeAll(tasks);}
067   * </pre>
068   *
069   * @return A list of {@code ListenableFuture} instances representing the tasks, in the same
070   *     sequential order as produced by the iterator for the given task list, each of which has
071   *     completed.
072   * @throws RejectedExecutionException {@inheritDoc}
073   * @throws NullPointerException if any task is null
074   */
075  @Override
076  <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
077      throws InterruptedException;
078
079  /**
080   * {@inheritDoc}
081   *
082   * <p>All elements in the returned list must be {@link ListenableFuture} instances. The easiest
083   * way to obtain a {@code List<ListenableFuture<T>>} from this method is an unchecked (but safe)
084   * cast:<pre>
085   *   {@code @SuppressWarnings("unchecked") // guaranteed by invokeAll contract}
086   *   {@code List<ListenableFuture<T>> futures = (List) executor.invokeAll(tasks, timeout, unit);}
087   * </pre>
088   *
089   * @return a list of {@code ListenableFuture} instances representing the tasks, in the same
090   *     sequential order as produced by the iterator for the given task list. If the operation did
091   *     not time out, each task will have completed. If it did time out, some of these tasks will
092   *     not have completed.
093   * @throws RejectedExecutionException {@inheritDoc}
094   * @throws NullPointerException if any task is null
095   */
096  @Override
097  <T> List<Future<T>> invokeAll(
098      Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
099      throws InterruptedException;
100}