| /* |
| * Copyright (C) 2008 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
| * in compliance with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software distributed under the License |
| * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
| * or implied. See the License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| |
| package com.google.common.util.concurrent; |
| |
| import com.google.common.annotations.GwtIncompatible; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.FutureTask; |
| import org.checkerframework.checker.nullness.compatqual.NullableDecl; |
| |
| /** |
| * A {@link FutureTask} that also implements the {@link ListenableFuture} interface. Unlike {@code |
| * FutureTask}, {@code ListenableFutureTask} does not provide an overrideable {@link |
| * FutureTask#done() done()} method. For similar functionality, call {@link #addListener}. |
| * |
| * <p>Few users should use this class. It is intended primarily for those who are implementing an |
| * {@code ExecutorService}. Most users should call {@link ListeningExecutorService#submit(Callable) |
| * ListeningExecutorService.submit} on a service obtained from {@link |
| * MoreExecutors#listeningDecorator}. |
| * |
| * @author Sven Mawson |
| * @since 1.0 |
| */ |
| @GwtIncompatible |
| public class ListenableFutureTask<V> extends FutureTask<V> implements ListenableFuture<V> { |
| // TODO(cpovirk): explore ways of making ListenableFutureTask final. There are some valid reasons |
| // such as BoundedQueueExecutorService to allow extends but it would be nice to make it final to |
| // avoid unintended usage. |
| |
| // The execution list to hold our listeners. |
| private final ExecutionList executionList = new ExecutionList(); |
| |
| /** |
| * Creates a {@code ListenableFutureTask} that will upon running, execute the given {@code |
| * Callable}. |
| * |
| * @param callable the callable task |
| * @since 10.0 |
| */ |
| public static <V> ListenableFutureTask<V> create(Callable<V> callable) { |
| return new ListenableFutureTask<V>(callable); |
| } |
| |
| /** |
| * Creates a {@code ListenableFutureTask} that will upon running, execute the given {@code |
| * Runnable}, and arrange that {@code get} will return the given result on successful completion. |
| * |
| * @param runnable the runnable task |
| * @param result the result to return on successful completion. If you don't need a particular |
| * result, consider using constructions of the form: {@code ListenableFuture<?> f = |
| * ListenableFutureTask.create(runnable, null)} |
| * @since 10.0 |
| */ |
| public static <V> ListenableFutureTask<V> create(Runnable runnable, @NullableDecl V result) { |
| return new ListenableFutureTask<V>(runnable, result); |
| } |
| |
| ListenableFutureTask(Callable<V> callable) { |
| super(callable); |
| } |
| |
| ListenableFutureTask(Runnable runnable, @NullableDecl V result) { |
| super(runnable, result); |
| } |
| |
| @Override |
| public void addListener(Runnable listener, Executor exec) { |
| executionList.add(listener, exec); |
| } |
| |
| /** Internal implementation detail used to invoke the listeners. */ |
| @Override |
| protected void done() { |
| executionList.execute(); |
| } |
| } |