org.jgroups.blocks.executor
Class ExecutionCompletionService<V>

java.lang.Object
  org.jgroups.blocks.executor.ExecutionCompletionService<V>

All Implemented Interfaces:

java.util.concurrent.CompletionService<V>

public class ExecutionCompletionService<V>
extends java.lang.Object
implements java.util.concurrent.CompletionService<V>

A CompletionService that uses a supplied ExecutionService to execute tasks. This class arranges that submitted tasks are, upon completion, placed on a queue accessible using take. The class is lightweight enough to be suitable for transient use when processing groups of tasks.

This class must be used instead of a ExecutorCompletionService provided from java.util.concurrent package. The 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.

Nested Class Summary

protected class

ExecutionCompletionService.QueueingListener

Field Summary

protected java.util.concurrent.BlockingQueue<NotifyingFuture<V>>	completionQueue
protected ExecutionService	executor
protected ExecutionCompletionService.QueueingListener	listener

Constructor Summary

	ExecutionCompletionService(ExecutionService executor) Creates an ExecutorCompletionService using the supplied executor for base task execution and a LinkedBlockingQueue as a completion queue.
	ExecutionCompletionService(ExecutionService executor, java.util.concurrent.BlockingQueue<NotifyingFuture<V>> completionQueue) Creates an ExecutorCompletionService using the supplied executor for base task execution and the supplied queue as its completion queue.
protected	ExecutionCompletionService(ExecutionService executor, java.util.concurrent.BlockingQueue<NotifyingFuture<V>> completionQueue, ExecutionCompletionService.QueueingListener listener) This constructor is here if someone wants to override this class and provide their own QueueingListener to possibly listen in on futures being finished

Method Summary

NotifyingFuture<V>	poll()
NotifyingFuture<V>	poll(long timeout, java.util.concurrent.TimeUnit unit)
java.util.concurrent.Future<V>	submit(java.util.concurrent.Callable<V> task)
java.util.concurrent.Future<V>	submit(java.lang.Runnable task, V result)
NotifyingFuture<V>	take()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

executor

protected final ExecutionService executor

completionQueue

protected final java.util.concurrent.BlockingQueue<NotifyingFuture<V>> completionQueue

listener

protected final ExecutionCompletionService.QueueingListener listener

Constructor Detail

ExecutionCompletionService

public ExecutionCompletionService(ExecutionService executor)

Creates an ExecutorCompletionService using the supplied executor for base task execution and a LinkedBlockingQueue as a completion queue.

Parameters:

executor - the executor to use

Throws:

java.lang.NullPointerException - if executor is null

ExecutionCompletionService

public ExecutionCompletionService(ExecutionService executor,
                                  java.util.concurrent.BlockingQueue<NotifyingFuture<V>> completionQueue)

Creates an ExecutorCompletionService using the supplied executor for base task execution and the supplied queue as its completion queue.

Parameters:

executor - the executor to use

completionQueue - the queue to use as the completion queue normally one dedicated for use by this service

Throws:

java.lang.NullPointerException - if executor is null

ExecutionCompletionService

protected ExecutionCompletionService(ExecutionService executor,
                                     java.util.concurrent.BlockingQueue<NotifyingFuture<V>> completionQueue,
                                     ExecutionCompletionService.QueueingListener listener)

This constructor is here if someone wants to override this class and provide their own QueueingListener to possibly listen in on futures being finished

Parameters:

executor - the executor to use

completionQueue - the queue to use as the completion queue normally one dedicated for use by this service

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:

java.lang.NullPointerException - if executor is null

Method Detail

submit

public java.util.concurrent.Future<V> submit(java.util.concurrent.Callable<V> task)

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.

Specified by:

submit in interface java.util.concurrent.CompletionService<V>

submit

public java.util.concurrent.Future<V> submit(java.lang.Runnable task,
                                             V result)

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.

Specified by:

submit in interface java.util.concurrent.CompletionService<V>

take

public NotifyingFuture<V> take()
                        throws java.lang.InterruptedException

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.

Specified by:

take in interface java.util.concurrent.CompletionService<V>

Throws:

java.lang.InterruptedException

poll

public NotifyingFuture<V> poll()

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.

Specified by:

poll in interface java.util.concurrent.CompletionService<V>

poll

public NotifyingFuture<V> poll(long timeout,
                               java.util.concurrent.TimeUnit unit)
                        throws java.lang.InterruptedException

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.

Specified by:

poll in interface java.util.concurrent.CompletionService<V>

Throws:

java.lang.InterruptedException