org.w3c.util
Class ThreadCache

java.lang.Object
  org.w3c.util.ThreadCache

public class ThreadCache
extends java.lang.Object

Field Summary

protected int	cachesize Number of cached threads.
protected org.w3c.util.CachedThread	freelist List of free threads.
protected org.w3c.util.CachedThread	freetail
protected java.lang.ThreadGroup	group The thread group for this thread cache.
protected boolean	growasneeded Should we queue thread requests, rather then creating new threads.
protected int	idlethreads Number of idle threads to always maintain alive.
protected int	idletimeout The idle timeout, for a thread to wait before being killed.
protected boolean	inited Has this thread cache been initialized ?
protected int	threadcount Number of created threads.
protected int	threadid Uniq thread identifier within this ThreadCache instance.
protected int	threadpriority Cached thread priority.
protected int	usedthreads Number of used threads

Constructor Summary

ThreadCache(java.lang.String name)
Create a thread cache, after creating a new thread group.

ThreadCache(java.lang.ThreadGroup group)
Create a thread cache, whose threads are to be children of the group.

ThreadCache(java.lang.ThreadGroup parent, java.lang.String name)
Create a thread cache, after creating a new thread group.

Method Summary

protected org.w3c.util.CachedThread	allocateThread(boolean waitp) Allocate a new thread, as requested.
boolean	getThread(java.lang.Runnable runnable, boolean waitp) Request a thread to run on the given object.
java.lang.ThreadGroup	getThreadGroup() Get the ThreadGroup managed by this ThreadCache instance.
int	getThreadPriority() Get the cached thread normal priority.
void	initialize() Initialize the given thread cache.
void	setCachesize(int cachesize) Set the thread cache size.
void	setCachesize(int cachesize, boolean update) Set the thread cache size.
void	setGrowAsNeeded(boolean onoff) Enable/disable the thread cache to grow as needed.
void	setIdleTimeout(int idletimeout) Set the idle timeout.
void	setThreadPriority(int priority) Set all the cached threads priority.
void	waitForCompletion() Wait until all the threads have finished their duty

Methods inherited from class java.lang.Object

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

Field Detail

inited

protected boolean inited

Has this thread cache been initialized ?

group

protected java.lang.ThreadGroup group

The thread group for this thread cache.

cachesize

protected int cachesize

Number of cached threads.

threadcount

protected int threadcount

Number of created threads.

threadid

protected int threadid

Uniq thread identifier within this ThreadCache instance.

idlethreads

protected int idlethreads

Number of idle threads to always maintain alive.

growasneeded

protected boolean growasneeded

Should we queue thread requests, rather then creating new threads.

usedthreads

protected int usedthreads

Number of used threads

freelist

protected org.w3c.util.CachedThread freelist

List of free threads.

freetail

protected org.w3c.util.CachedThread freetail

idletimeout

protected int idletimeout

The idle timeout, for a thread to wait before being killed. Defaults to 5000 milliseconds.

threadpriority

protected int threadpriority

Cached thread priority.

Constructor Detail

ThreadCache

public ThreadCache(java.lang.ThreadGroup group)

Create a thread cache, whose threads are to be children of the group.

Parameters:

group - The thread group to which this thread cache is bound.

nstart - Number of thread to create in advance.

ThreadCache

public ThreadCache(java.lang.String name)

Create a thread cache, after creating a new thread group.

Parameters:

name - The name of the thread group to create.

ThreadCache

public ThreadCache(java.lang.ThreadGroup parent,
                   java.lang.String name)

Create a thread cache, after creating a new thread group.

Parameters:

parent - The parent of the thread group to create.

name - The name of the thread group.

Method Detail

allocateThread

protected org.w3c.util.CachedThread allocateThread(boolean waitp)

Allocate a new thread, as requested.

Parameters:

waitp - Should we wait until a thread is available ?

Returns:

A launched CachedThread instance, or null if unable to allocate a new thread, and waitp is false.

setCachesize

public void setCachesize(int cachesize,
                         boolean update)

Set the thread cache size. This will also update the number of idle threads to maintain, if requested.

Parameters:

cachesize - The new thread cache size.

update - If true also update the number of threads to maintain idle.

setCachesize

public void setCachesize(int cachesize)

Set the thread cache size. Updaet the number of idle threads to keep alive.

Parameters:

cachesize - The new thread cache size.

setGrowAsNeeded

public void setGrowAsNeeded(boolean onoff)

Enable/disable the thread cache to grow as needed. This flag should be turned on only if always getting a thread as fast as possible is critical.

Parameters:

onoff - The toggle.

setThreadPriority

public void setThreadPriority(int priority)

Set all the cached threads priority. Changing the cached thread priority should be done before the thread cache is initialized, it will not affect already created threads.

Parameters:

priority - The new cachewd threads priority.

getThreadPriority

public int getThreadPriority()

Get the cached thread normal priority.

Returns:

Currently assigned cached thread priority.

setIdleTimeout

public void setIdleTimeout(int idletimeout)

Set the idle timeout. The idle timeout value is used to eliminate threads that have remain idle for too long (although the thread cache will ensure that a decent minimal number of threads stay around).

Parameters:

idletimeout - The new idle timeout.

getThread

public boolean getThread(java.lang.Runnable runnable,
                         boolean waitp)

Request a thread to run on the given object.

Parameters:

runnable - The object to run with the allocated thread.

waitp - If true wait until a free thread is available, otherwise, return false.

Returns:

A boolean, true if a thread was successfully allocated for the given object, false otherwise.

getThreadGroup

public java.lang.ThreadGroup getThreadGroup()

Get the ThreadGroup managed by this ThreadCache instance.

Returns:

A ThreadGroup instance.

waitForCompletion

public void waitForCompletion()

Wait until all the threads have finished their duty

initialize

public void initialize()

Initialize the given thread cache. This two stage initialize method is done so that configuration of the thread cache can be done before any thread get actually created.