/*
* JBoss, Home of Professional Open Source
* Copyright 2011 Red Hat Inc. and/or its affiliates and other
* contributors as indicated by the @author tags. All rights reserved.
* See the copyright.txt in the distribution for a full listing of
* individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.infinispan.distexec;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.Future;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import org.infinispan.util.concurrent.FutureListener;
import org.infinispan.util.concurrent.NotifyingFuture;
/**
* A {@link CompletionService} that uses a supplied {@link DistributedExecutorService}
* to execute tasks. This class arranges that submitted tasks are,
* upon completion, placed on a queue accessible using <tt>take</tt>.
* The class is lightweight enough to be suitable for transient use
* when processing groups of tasks.
* <p>
* This class must be used instead of a {@link ExecutorCompletionService}
* provided from java.util.concurrent package. The
* {@link ExecutorCompletionService} may not be used since it requires the use
* of a non serializable RunnableFuture object. Since a ExecutionService
* may only be used with serializable request objects, this class must be used
* instead.
*/
public class DistributedExecutionCompletionService<V> implements CompletionService<V> {
protected final DistributedExecutorService executor;
protected final BlockingQueue<NotifyingFuture<V>> completionQueue;
protected final QueueingListener listener;
protected class QueueingListener implements FutureListener<V> {
@Override
public void futureDone(Future<V> future) {
// This is a safe cast since this listener should only used
// in this class
completionQueue.add((NotifyingFuture<V>)future);
}
}
/**
* Creates an ExecutorCompletionService using the supplied
* executor for base task execution and a
* {@link LinkedBlockingQueue} as a completion queue.
*
* @param executor the executor to use
* @throws NullPointerException if executor is <tt>null</tt>
*/
public DistributedExecutionCompletionService(DistributedExecutorService executor) {
this(executor, null, null);
}
/**
* Creates an ExecutorCompletionService using the supplied
* executor for base task execution and the supplied queue as its
* completion queue.
*
* @param executor the executor to use
* @param completionQueue the queue to use as the completion queue
* normally one dedicated for use by this service
* @throws NullPointerException if executor is <tt>null</tt>
*/
public DistributedExecutionCompletionService(DistributedExecutorService executor,
BlockingQueue<NotifyingFuture<V>> completionQueue) {
this(executor, completionQueue, null);
}
/**
* This constructor is here if someone wants to override this class and
* provide their own QueueingListener to possibly listen in on futures
* being finished
* @param executor the executor to use
* @param completionQueue the queue to use as the completion queue
* normally one dedicated for use by this service
* @param listener the listener to notify. To work properly this listner
* should at minimum call the super.futureDone or else this
* completion service may not work correctly.
* @throws NullPointerException if executor is <tt>null</tt>
*/
protected DistributedExecutionCompletionService(DistributedExecutorService executor,
BlockingQueue<NotifyingFuture<V>> completionQueue,
QueueingListener listener) {
if (executor == null)
throw new NullPointerException();
this.executor = executor;
if (completionQueue == null) {
this.completionQueue = new LinkedBlockingQueue<NotifyingFuture<V>>();
}
else {
this.completionQueue = completionQueue;
}
if (listener == null) {
this.listener = new QueueingListener();
}
else {
this.listener = listener;
}
}
/**
* {@inheritDoc CompletionService}
* <p>
* This future object may not be used as a NotifyingFuture. That is because
* internally this class sets the listener to provide ability to add to the queue.
*/
@Override
public Future<V> submit(Callable<V> task) {
if (task == null) throw new NullPointerException();
NotifyingFuture<V> f = (NotifyingFuture<V>) executor.submit(task);
f.attachListener(listener);
return f;
}
/**
* {@inheritDoc CompletionService}
* <p>
* This future object may not be used as a NotifyingFuture. That is because
* internally this class sets the listener to provide ability to add to the queue.
*/
@Override
public Future<V> submit(Runnable task, V result) {
if (task == null) throw new NullPointerException();
NotifyingFuture<V> f = (NotifyingFuture<V>) executor.submit(task, result);
f.attachListener(listener);
return f;
}
/**
* {@inheritDoc CompletionService}
* <p>
* This future may safely be used as a NotifyingFuture if desired. This
* is because if it tries to set a listener it will be called immediately
* since the task has already been completed.
*/
@Override
public NotifyingFuture<V> take() throws InterruptedException {
return completionQueue.take();
}
/**
* {@inheritDoc CompletionService}
* <p>
* This future may safely be used as a NotifyingFuture if desired. This
* is because if it tries to set a listener it will be called immediately
* since the task has already been completed.
*/
@Override
public NotifyingFuture<V> poll() {
return completionQueue.poll();
}
/**
* {@inheritDoc CompletionService}
* <p>
* This future may safely be used as a NotifyingFuture if desired. This
* is because if it tries to set a listener it will be called immediately
* since the task has already been completed.
*/
@Override
public NotifyingFuture<V> poll(long timeout, TimeUnit unit) throws InterruptedException {
return completionQueue.poll(timeout, unit);
}
public <K> Future<V> submit(Callable<V> task, K... input) {
NotifyingFuture<V> f = (NotifyingFuture<V>) executor.submit(task, input);
f.attachListener(listener);
return f;
}
public List<Future<V>> submitEverywhere(Callable<V> task) {
List<Future<V>> fl = executor.submitEverywhere(task);
for (Future<V> f : fl) {
((NotifyingFuture<V>) f).attachListener(listener);
}
return fl;
}
public <K> List<Future<V>> submitEverywhere(Callable<V> task, K... input) {
List<Future<V>> fl = executor.submitEverywhere(task, input);
for (Future<V> f : fl) {
((NotifyingFuture<V>) f).attachListener(listener);
}
return fl;
}
}