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.annotations.GwtCompatible;
import com.google.common.base.Preconditions;
import com.google.common.collect.ForwardingObject;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* 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
*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class ForwardingFuture extends ForwardingObject
implements Future {
/** Constructor for use by subclasses. */
protected ForwardingFuture() {}
@Override
protected abstract Future delegate();
@Override
@CanIgnoreReturnValue
public boolean cancel(boolean mayInterruptIfRunning) {
return delegate().cancel(mayInterruptIfRunning);
}
@Override
public boolean isCancelled() {
return delegate().isCancelled();
}
@Override
public boolean isDone() {
return delegate().isDone();
}
@Override
@CanIgnoreReturnValue
@ParametricNullness
public V get() throws InterruptedException, ExecutionException {
return delegate().get();
}
@Override
@CanIgnoreReturnValue
@ParametricNullness
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;
}
}
}