Java tutorial
/* * Copyright 2013 The Netty Project * * The Netty Project licenses this file to you 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 io.netty.util.concurrent; import java.util.concurrent.CancellationException; import java.util.concurrent.TimeUnit; /** * The result of an asynchronous operation. */ @SuppressWarnings("ClassNameSameAsAncestorName") public interface Future<V> extends java.util.concurrent.Future<V> { /** * Returns {@code true} if and only if the I/O operation was completed * successfully. */ boolean isSuccess(); /** * returns {@code true} if and only if the operation can be cancelled via {@link #cancel(boolean)}. */ boolean isCancellable(); /** * Returns the cause of the failed I/O operation if the I/O operation has * failed. * * @return the cause of the failure. * {@code null} if succeeded or this future is not * completed yet. */ Throwable cause(); /** * Adds the specified listener to this future. The * specified listener is notified when this future is * {@linkplain #isDone() done}. If this future is already * completed, the specified listener is notified immediately. */ Future<V> addListener(GenericFutureListener<? extends Future<? super V>> listener); /** * Adds the specified listeners to this future. The * specified listeners are notified when this future is * {@linkplain #isDone() done}. If this future is already * completed, the specified listeners are notified immediately. */ Future<V> addListeners(GenericFutureListener<? extends Future<? super V>>... listeners); /** * Removes the first occurrence of the specified listener from this future. * The specified listener is no longer notified when this * future is {@linkplain #isDone() done}. If the specified * listener is not associated with this future, this method * does nothing and returns silently. */ Future<V> removeListener(GenericFutureListener<? extends Future<? super V>> listener); /** * Removes the first occurrence for each of the listeners from this future. * The specified listeners are no longer notified when this * future is {@linkplain #isDone() done}. If the specified * listeners are not associated with this future, this method * does nothing and returns silently. */ Future<V> removeListeners(GenericFutureListener<? extends Future<? super V>>... listeners); /** * Waits for this future until it is done, and rethrows the cause of the failure if this future * failed. */ Future<V> sync() throws InterruptedException; /** * Waits for this future until it is done, and rethrows the cause of the failure if this future * failed. */ Future<V> syncUninterruptibly(); /** * Waits for this future to be completed. * * @throws InterruptedException * if the current thread was interrupted */ Future<V> await() throws InterruptedException; /** * Waits for this future to be completed without * interruption. This method catches an {@link InterruptedException} and * discards it silently. */ Future<V> awaitUninterruptibly(); /** * Waits for this future to be completed within the * specified time limit. * * @return {@code true} if and only if the future was completed within * the specified time limit * * @throws InterruptedException * if the current thread was interrupted */ boolean await(long timeout, TimeUnit unit) throws InterruptedException; /** * Waits for this future to be completed within the * specified time limit. * * @return {@code true} if and only if the future was completed within * the specified time limit * * @throws InterruptedException * if the current thread was interrupted */ boolean await(long timeoutMillis) throws InterruptedException; /** * Waits for this future to be completed within the * specified time limit without interruption. This method catches an * {@link InterruptedException} and discards it silently. * * @return {@code true} if and only if the future was completed within * the specified time limit */ boolean awaitUninterruptibly(long timeout, TimeUnit unit); /** * Waits for this future to be completed within the * specified time limit without interruption. This method catches an * {@link InterruptedException} and discards it silently. * * @return {@code true} if and only if the future was completed within * the specified time limit */ boolean awaitUninterruptibly(long timeoutMillis); /** * Return the result without blocking. If the future is not done yet this will return {@code null}. * * As it is possible that a {@code null} value is used to mark the future as successful you also need to check * if the future is really done with {@link #isDone()} and not rely on the returned {@code null} value. */ V getNow(); /** * {@inheritDoc} * * If the cancellation was successful it will fail the future with a {@link CancellationException}. */ @Override boolean cancel(boolean mayInterruptIfRunning); }