/*
* Copyright (c) 2014 Brocade Communications Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.util.concurrent;
import com.google.common.base.MoreObjects;
import com.google.common.base.MoreObjects.ToStringHelper;
import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.AbstractListeningExecutorService;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
/**
* An {@link com.google.common.util.concurrent.ListeningExecutorService}
* implementation that also allows for an {@link Executor} to be specified on
* construction that is used to execute {@link ListenableFuture} callback
* Runnables, registered via
* {@link com.google.common.util.concurrent.Futures#addCallback} or
* {@link ListenableFuture#addListener} directly, asynchronously when a task
* that is run on this executor completes. This is useful when you want to
* guarantee listener callback executions are off-loaded onto another thread to
* avoid blocking the thread that completed the task, as a common use case is to
* pass an executor that runs tasks in the same thread as the caller (ie
* MoreExecutors#sameThreadExecutor
}) to
* {@link ListenableFuture#addListener}.
*
*
* Most commonly, this class would be used in lieu of
* MoreExecutors#listeningDecorator
when the underlying delegate
* Executor is single-threaded, in which case, you may not want ListenableFuture
* callbacks to block the single thread.
*
*
* Note: the Executor specified on construction does not replace the Executor
* specified in {@link ListenableFuture#addListener}. The latter Executor is
* still used however, if it is detected that the listener Runnable would
* execute in the thread that completed the task, the listener is executed on
* Executor specified on construction.
*
* @author Thomas Pantelis
* @see AsyncNotifyingListenableFutureTask
*/
public class AsyncNotifyingListeningExecutorService extends AbstractListeningExecutorService {
private final ExecutorService delegate;
private final Executor listenableFutureExecutor;
/**
* Constructor.
*
* @param delegate the back-end ExecutorService.
* @param listenableFutureExecutor the executor used to run listener callbacks asynchronously.
* If null, no executor is used.
*/
public AsyncNotifyingListeningExecutorService( final ExecutorService delegate,
@Nullable final Executor listenableFutureExecutor ) {
this.delegate = Preconditions.checkNotNull( delegate );
this.listenableFutureExecutor = listenableFutureExecutor;
}
/**
* Creates an {@link AsyncNotifyingListenableFutureTask} instance with the listener Executor.
*
* @param task the Callable to execute
*/
private