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.DoNotMock;
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;
026import org.checkerframework.checker.nullness.qual.Nullable;
027
028/**
029 * An {@link ExecutorService} that returns {@link ListenableFuture} instances. To create an instance
030 * from an existing {@link ExecutorService}, call {@link
031 * MoreExecutors#listeningDecorator(ExecutorService)}.
032 *
033 * @author Chris Povirk
034 * @since 10.0
035 */
036@DoNotMock(
037    "Use TestingExecutors.sameThreadScheduledExecutor, or wrap a real Executor from "
038        + "java.util.concurrent.Executors with MoreExecutors.listeningDecorator")
039@GwtIncompatible
040@ElementTypesAreNonnullByDefault
041public interface ListeningExecutorService extends ExecutorService {
042  /**
043   * @return a {@code ListenableFuture} representing pending completion of the task
044   * @throws RejectedExecutionException {@inheritDoc}
045   */
046  @Override
047  <T extends @Nullable Object> ListenableFuture<T> submit(Callable<T> task);
048
049  /**
050   * @return a {@code ListenableFuture} representing pending completion of the task
051   * @throws RejectedExecutionException {@inheritDoc}
052   */
053  @Override
054  ListenableFuture<?> submit(Runnable task);
055
056  /**
057   * @return a {@code ListenableFuture} representing pending completion of the task
058   * @throws RejectedExecutionException {@inheritDoc}
059   */
060  @Override
061  <T extends @Nullable Object> ListenableFuture<T> submit(
062      Runnable task, @ParametricNullness T result);
063
064  /**
065   * {@inheritDoc}
066   *
067   * <p>All elements in the returned list must be {@link ListenableFuture} instances. The easiest
068   * way to obtain a {@code List<ListenableFuture<T>>} from this method is an unchecked (but safe)
069   * cast:
070   *
071   * <pre>
072   *   {@code @SuppressWarnings("unchecked") // guaranteed by invokeAll contract}
073   *   {@code List<ListenableFuture<T>> futures = (List) executor.invokeAll(tasks);}
074   * </pre>
075   *
076   * @return A list of {@code ListenableFuture} instances representing the tasks, in the same
077   *     sequential order as produced by the iterator for the given task list, each of which has
078   *     completed.
079   * @throws RejectedExecutionException {@inheritDoc}
080   * @throws NullPointerException if any task is null
081   */
082  @Override
083  <T extends @Nullable Object> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
084      throws InterruptedException;
085
086  /**
087   * {@inheritDoc}
088   *
089   * <p>All elements in the returned list must be {@link ListenableFuture} instances. The easiest
090   * way to obtain a {@code List<ListenableFuture<T>>} from this method is an unchecked (but safe)
091   * cast:
092   *
093   * <pre>
094   *   {@code @SuppressWarnings("unchecked") // guaranteed by invokeAll contract}
095   *   {@code List<ListenableFuture<T>> futures = (List) executor.invokeAll(tasks, timeout, unit);}
096   * </pre>
097   *
098   * @return a list of {@code ListenableFuture} instances representing the tasks, in the same
099   *     sequential order as produced by the iterator for the given task list. If the operation did
100   *     not time out, each task will have completed. If it did time out, some of these tasks will
101   *     not have completed.
102   * @throws RejectedExecutionException {@inheritDoc}
103   * @throws NullPointerException if any task is null
104   */
105  @Override
106  <T extends @Nullable Object> List<Future<T>> invokeAll(
107      Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
108      throws InterruptedException;
109}