/*
* 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.Beta;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.FutureTask;
import javax.annotation.Nullable;
/**
* A {@link FutureTask} that also implements the {@link ListenableFuture}
* interface. Subclasses must make sure to call {@code super.done()} if they
* also override the {@link #done()} method, otherwise the listeners will not
* be called.
*
* @author Sven Mawson
* @since 1.0
*/
public final class ListenableFutureTask<V> extends FutureTask<V>
implements ListenableFuture<V> {
// 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, @Nullable V result) {
return new ListenableFutureTask<V>(runnable, result);
}
/**
* <b>Deprecated.</b> Use {@link #create(Callable)} instead. This method will be
* removed from Guava in Guava release 11.0.
*
* Creates a {@code ListenableFutureTask} that will upon running, execute the
* given {@code Callable}.
*
* @param callable the callable task
*/
@Beta @Deprecated public
ListenableFutureTask(Callable<V> callable) {
super(callable);
}
/**
* <b>Deprecated. Use {@link #create(Runnable, Object)} instead. This method
* will be removed from Guava in Guava release 11.0.</b>
*
* 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)}
*/
@Beta @Deprecated public
ListenableFutureTask(Runnable runnable, @Nullable V result) {
super(runnable, result);
}
@Override
public void addListener(Runnable listener, Executor exec) {
executionList.add(listener, exec);
}
@Override
protected void done() {
executionList.execute();
}
}
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