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
017package com.google.common.util.concurrent;
018
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
030 * {@link MoreExecutors#listeningDecorator(ExecutorService)}.
031 *
032 * @author Chris Povirk
033 * @since 10.0
034 */
035public interface ListeningExecutorService extends ExecutorService {
036  /**
037   * @return a {@code ListenableFuture} representing pending completion of the task
038   * @throws RejectedExecutionException {@inheritDoc}
039   */
040  @Override
041  <T> ListenableFuture<T> submit(Callable<T> task);
042
043  /**
044   * @return a {@code ListenableFuture} representing pending completion of the task
045   * @throws RejectedExecutionException {@inheritDoc}
046   */
047  @Override
048  ListenableFuture<?> submit(Runnable task);
049
050  /**
051   * @return a {@code ListenableFuture} representing pending completion of the task
052   * @throws RejectedExecutionException {@inheritDoc}
053   */
054  @Override
055  <T> ListenableFuture<T> submit(Runnable task, T result);
056
057  /**
058   * {@inheritDoc}
059   *
060   * <p>All elements in the returned list must be {@link ListenableFuture} instances. The easiest
061   * way to obtain a {@code List<ListenableFuture<T>>} from this method is an unchecked (but safe)
062   * cast:<pre>
063   *   {@code @SuppressWarnings("unchecked") // guaranteed by invokeAll contract}
064   *   {@code List<ListenableFuture<T>> futures = (List) executor.invokeAll(tasks);}
065   * </pre>
066   *
067   * @return A list of {@code ListenableFuture} instances representing the tasks, in the same
068   *         sequential order as produced by the iterator for the given task list, each of which has
069   *         completed.
070   * @throws RejectedExecutionException {@inheritDoc}
071   * @throws NullPointerException if any task is null
072   */
073  @Override
074  <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
075      throws InterruptedException;
076
077  /**
078   * {@inheritDoc}
079   *
080   * <p>All elements in the returned list must be {@link ListenableFuture} instances. The easiest
081   * way to obtain a {@code List<ListenableFuture<T>>} from this method is an unchecked (but safe)
082   * cast:<pre>
083   *   {@code @SuppressWarnings("unchecked") // guaranteed by invokeAll contract}
084   *   {@code List<ListenableFuture<T>> futures = (List) executor.invokeAll(tasks, timeout, unit);}
085   * </pre>
086   *
087   * @return a list of {@code ListenableFuture} instances representing the tasks, in the same
088   *         sequential order as produced by the iterator for the given task list. If the operation
089   *         did not time out, each task will have completed. If it did time out, some of these
090   *         tasks will not have completed.
091   * @throws RejectedExecutionException {@inheritDoc}
092   * @throws NullPointerException if any task is null
093   */
094  @Override
095  <T> List<Future<T>> invokeAll(
096      Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
097      throws InterruptedException;
098}