org.jboss.util

Class WorkerQueue

java.lang.Object

org.jboss.util.WorkerQueue

Direct Known Subclasses:

TimerQueue

public class WorkerQueue
extends java.lang.Object

Class that queues Executable jobs that are executed sequentially by a single thread.

Version:

$Revision$

See Also:

Executable

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	WorkerQueue.JobItem Simple linked cell, that has only a reference to the next job.
protected class	WorkerQueue.QueueLoop Class that loops getting the next job to be executed and then executing it, in the worker thread.

Field Summary

Fields

Modifier and Type	Field and Description
private WorkerQueue.JobItem	m_currentJob The job that will be executed by the worker thread
protected java.lang.Thread	m_queueThread The thread that runs the Executable jobs

Constructor Summary

Constructors

Constructor and Description
WorkerQueue() Creates a new worker queue with default thread name of "Worker Thread"
WorkerQueue(java.lang.String threadName) Creates a new worker queue with the specified thread name
WorkerQueue(java.lang.String threadName, boolean isDaemon) Creates a new worker queue with the specified thread name and daemon mode flag

Method Summary

Modifier and Type	Method and Description
protected void	clear() Clears the running thread after the queue has been stopped.
protected java.lang.Runnable	createQueueLoop() Creates the loop that will get the next job and process it.
protected Executable	getJob() Called by this class, this method checks if the queue is empty; if it is, then waits, else returns the current job.
protected Executable	getJobImpl() Never call this method, only override in subclasses to perform job getting in a specific way, normally tied to the data structure holding the jobs.
protected boolean	isInterrupted()
void	putJob(Executable job) Called by a thread that is not the WorkerQueue thread, this method queues the job and, if necessary, wakes up this worker queue that is waiting in getJob().
protected void	putJobImpl(Executable job) Never call this method, only override in subclasses to perform job adding in a specific way, normally tied to the data structure holding the jobs.
void	start() Starts the worker queue.
void	stop() Stops nicely the worker queue.

Methods inherited from class java.lang.Object

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

Field Detail

m_queueThread

protected java.lang.Thread m_queueThread

The thread that runs the Executable jobs

m_currentJob

private WorkerQueue.JobItem m_currentJob

The job that will be executed by the worker thread

Constructor Detail

WorkerQueue

public WorkerQueue()

Creates a new worker queue with default thread name of "Worker Thread"

WorkerQueue

public WorkerQueue(java.lang.String threadName)

Creates a new worker queue with the specified thread name

Parameters:

threadName -

WorkerQueue

public WorkerQueue(java.lang.String threadName,
                   boolean isDaemon)

Creates a new worker queue with the specified thread name and daemon mode flag

Parameters:

threadName -

isDaemon -

Method Detail

start

public void start()

Starts the worker queue.

See Also:

stop()

stop

public void stop()

Stops nicely the worker queue.
After this call trying to put a new job will result in a InterruptedException to be thrown. The jobs queued before and not yet processed are processed until the queue is empty, then this worker queue is cleared.

See Also:

clear(), start(), isInterrupted()

putJob

public void putJob(Executable job)

Called by a thread that is not the WorkerQueue thread, this method queues the job and, if necessary, wakes up this worker queue that is waiting in getJob().

Parameters:

job -

isInterrupted

protected boolean isInterrupted()

Returns:

whether the worker thread has been interrupted.
When this method returns true, it is not possible to put new jobs in the queue and the already present jobs are executed and removed from the queue, then the thread exits.

See Also:

stop()

getJob

protected Executable getJob()
                     throws java.lang.InterruptedException

Called by this class, this method checks if the queue is empty; if it is, then waits, else returns the current job.

Returns:

the executable

Throws:

java.lang.InterruptedException

See Also:

putJob(org.jboss.util.Executable)

getJobImpl

protected Executable getJobImpl()
                         throws java.lang.InterruptedException

Never call this method, only override in subclasses to perform job getting in a specific way, normally tied to the data structure holding the jobs.

Returns:

the exectuable

Throws:

java.lang.InterruptedException

putJobImpl

protected void putJobImpl(Executable job)

Never call this method, only override in subclasses to perform job adding in a specific way, normally tied to the data structure holding the jobs.

Parameters:

job -

clear

protected void clear()

Clears the running thread after the queue has been stopped.
After this call, this worker queue is unusable and can be garbaged.

createQueueLoop

protected java.lang.Runnable createQueueLoop()

Creates the loop that will get the next job and process it.
Override in subclasses to create a custom loop.

Returns:

the runnable