com.google.common.util.concurrent.ForwardingFuture Maven / Gradle / Ivy
/*
* Copyright (C) 2009 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.base.Preconditions;
import com.google.common.collect.ForwardingObject;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* A {@link Future} which forwards all its method calls to another future.
* Subclasses should override one or more methods to modify the behavior of
* the backing future as desired per the decorator pattern.
*
* Most subclasses can just use {@link SimpleForwardingFuture}.
*
* @author Sven Mawson
* @since 1.0
*/
public abstract class ForwardingFuture extends ForwardingObject
implements Future {
/** Constructor for use by subclasses. */
protected ForwardingFuture() {}
@Override protected abstract Future delegate();
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
return delegate().cancel(mayInterruptIfRunning);
}
@Override
public boolean isCancelled() {
return delegate().isCancelled();
}
@Override
public boolean isDone() {
return delegate().isDone();
}
@Override
public V get() throws InterruptedException, ExecutionException {
return delegate().get();
}
@Override
public V get(long timeout, TimeUnit unit)
throws InterruptedException, ExecutionException, TimeoutException {
return delegate().get(timeout, unit);
}
/*
* TODO(cpovirk): Use standard Javadoc form for SimpleForwarding* class and
* constructor
*/
/**
* A simplified version of {@link ForwardingFuture} where subclasses
* can pass in an already constructed {@link Future} as the delegate.
*
* @since 9.0
*/
public abstract static class SimpleForwardingFuture
extends ForwardingFuture {
private final Future delegate;
protected SimpleForwardingFuture(Future delegate) {
this.delegate = Preconditions.checkNotNull(delegate);
}
@Override
protected final Future delegate() {
return delegate;
}
}
}