com.vividsolutions.jump.workbench.ui.renderer

Class ThreadQueue

java.lang.Object

com.vividsolutions.jump.workbench.ui.renderer.ThreadQueue

public class ThreadQueue
extends java.lang.Object

This thread queue executes at maximum N Runnables in parallel were N is a given number of worker threads that should be used. If N threads are running and busy each further incoming Runnable is queued until one of the threads has finished its current job. If a worker thread becomes idle (no more job in the queue) it is hold alive for 5 seconds. If during this period of time no new Runnable is enqueued the worker thread dies.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ThreadQueue.Listener If the number of running threads goes down to zero implementations of this interface are able to be informed.
protected class	ThreadQueue.Worker Worker thread.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	disposed Singals that the ThreadQueue is going to quit
protected java.util.ArrayList	listeners List of Listeners
protected int	maxRunningThreads max.
protected java.util.LinkedList	queuedRunnables The queue of Runnables jobs waiting to be run
protected int[]	runningThreads Number of running threads
protected int	waitingThreads Number of threads that are currently idle
static long	WORKER_STAY_ALIVE_TIME The time a worker thread stays alive if idle

Constructor Summary

Constructors

Constructor and Description
ThreadQueue() Creates a ThreadQueue with one worker thread.
ThreadQueue(int maxRunningThreads) Creates a ThreadQueue with a given number of worker threads.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(java.lang.Runnable runnable) Adds a Runnables to the queue.
void	add(ThreadQueue.Listener listener) Adds a Listener to this ThreadQueue.
void	clear() Empties the queue of waiting Runnables.
void	dispose() Shuts down the ThreadQueue.
protected void	fireAllRunningThreadsFinished() Informs Listeners of the fact that the number of running threads went to zero.
int	getRunningThreads() The number of currently running worker threads.
void	remove(ThreadQueue.Listener listener) Removes a Listener from this ThreadQueue.
int	runningThreads() The number of currently running worker threads.
int	waitingRunnables() The number of currently waiting Runnables.
int	waitingThreads() The number of currently idle worker threads.

Methods inherited from class java.lang.Object

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

Field Detail

WORKER_STAY_ALIVE_TIME

public static final long WORKER_STAY_ALIVE_TIME

The time a worker thread stays alive if idle

See Also:

Constant Field Values

runningThreads

protected int[] runningThreads

Number of running threads

maxRunningThreads

protected int maxRunningThreads

max. Number of threads running parallel

waitingThreads

protected int waitingThreads

Number of threads that are currently idle

queuedRunnables

protected java.util.LinkedList queuedRunnables

The queue of Runnables jobs waiting to be run

disposed

protected boolean disposed

Singals that the ThreadQueue is going to quit

listeners

protected java.util.ArrayList listeners

List of Listeners

Constructor Detail

ThreadQueue

public ThreadQueue()

Creates a ThreadQueue with one worker thread.

ThreadQueue

public ThreadQueue(int maxRunningThreads)

Creates a ThreadQueue with a given number of worker threads.

Parameters:

maxRunningThreads - the max. number of threads to be run parallel.

Method Detail

add

public void add(ThreadQueue.Listener listener)

Adds a Listener to this ThreadQueue.

Parameters:

listener - the listener to add.

remove

public void remove(ThreadQueue.Listener listener)

Removes a Listener from this ThreadQueue.

Parameters:

listener - the listener to be removed.

fireAllRunningThreadsFinished

protected void fireAllRunningThreadsFinished()

Informs Listeners of the fact that the number of running threads went to zero.

runningThreads

public int runningThreads()

The number of currently running worker threads.

Returns:

number of currently running worker threads.

getRunningThreads

public int getRunningThreads()

The number of currently running worker threads. Alias for runningThreads()

Returns:

number of currently running worker threads.

waitingRunnables

public int waitingRunnables()

The number of currently waiting Runnables.

Returns:

number of currently waiting Runnables.

waitingThreads

public int waitingThreads()

The number of currently idle worker threads.

Returns:

number of currently idle worker threads.

add

public void add(java.lang.Runnable runnable)

Adds a Runnables to the queue. It will be run in one of the worker threads.

Parameters:

runnable - The Runnables to add

clear

public void clear()

Empties the queue of waiting Runnables.

dispose

public void dispose()

Shuts down the ThreadQueue.