/*
 * 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.
/**
 * The result of an asynchronous operation.
 */
@SuppressWarnings("ClassNameSameAsAncestorName")
public interface Future<V> extends java.util.concurrent.Future<V> {

    
Returns true if and only if the I/O operation was completed successfully. /**
     * Returns {@code true} if and only if the I/O operation was completed
     * successfully.
     */
    boolean isSuccess();

    
returns true if and only if the operation can be cancelled via cancel(boolean). /**
     * 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.
Returns:
the cause of the failure. null if succeeded or this future is not completed yet./**
     * 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 done. If this future is already completed, the specified listener is notified immediately. /**
     * 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 done. If this future is already completed, the specified listeners are notified immediately. /**
     * 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 done. If the specified listener is not associated with this future, this method does nothing and returns silently. /**
     * 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 done. If the specified listeners are not associated with this future, this method does nothing and returns silently. /**
     * 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.
/**
     * 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.
/**
     * 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/**
     * 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 InterruptedException and discards it silently. /**
     * 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.
Throws:
InterruptedException – 
        if the current thread was interrupted
Returns:
true if and only if the future was completed within the specified time limit/**
     * 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.
Throws:
InterruptedException – 
        if the current thread was interrupted
Returns:
true if and only if the future was completed within the specified time limit/**
     * 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 InterruptedException and discards it silently. 
Returns:
true if and only if the future was completed within the specified time limit/**
     * 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 InterruptedException and discards it silently. 
Returns:
true if and only if the future was completed within the specified time limit/**
     * 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 null. As it is possible that a null value is used to mark the future as successful you also need to check if the future is really done with Future.isDone() and not relay on the returned null value. /**
     * 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 relay on the returned {@code null} value.
     */
    V getNow();

    
{@inheritDoc} If the cancellation was successful it will fail the future with an CancellationException. /**
     * {@inheritDoc}
     *
     * If the cancellation was successful it will fail the future with an {@link CancellationException}.
     */
    @Override
    boolean cancel(boolean mayInterruptIfRunning);
}