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

Nested Classes

Modifier and Type	Class and Description
protected class	ExecutionCompletionService.QueueingListener

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.concurrent.BlockingQueue<NotifyingFuture<V>>	completionQueue
protected ExecutionService	executor
protected ExecutionCompletionService.QueueingListener	listener

Constructor Summary

Constructors

Modifier	Constructor and Description
	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

Modifier and Type	Method and Description
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