com.antelmann.util
Class ThreadPool

java.lang.Object
  com.antelmann.util.ThreadPool

All Implemented Interfaces:

Executor

public class ThreadPool
extends Object
implements Executor

uses a pool of threads to execute tasks asynchronously and concurrently. ThreadPool was implemented before JDK1.5 and is somewhat simillar to ThreadPoolExecutor

Author:

Holger Antelmann

See Also:

ThreadWorker

Constructor Summary

ThreadPool(int numberOfThreads)

ThreadPool(int numberOfThreads, boolean asDaemon)

Method Summary

void	addListener(ThreadWorker.Listener listener)
int	addThread() adds one ThreadWorker to the pool and returns the current number of threads
void	execute(Runnable task) calls runTask(task); this method enables usability with jdk1.5
void	finishAll(boolean now) removes all ThreadWorkers, which will all end either after the current or the last queued task - depending on the 'now' parameter.
ThreadWorker.Listener[]	getListeners()
int	getNumberOfThreads() returns the number of all threads currently in this pool
int	getQueueSize() total queue size over all threads
int	idleThreads() returns the number of threads that are currently idle
boolean	isActive() returns true if at least one thread in the pool is currently active
boolean	removeIdleThread() attempts to remove a single ThreadWorker from the pool.
int	removeIdleThreads() removes all threads that are currently idle.
void	removeListener(ThreadWorker.Listener listener)
void	runTask(Runnable task)

Methods inherited from class java.lang.Object

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

Constructor Detail

ThreadPool

public ThreadPool(int numberOfThreads)

ThreadPool

public ThreadPool(int numberOfThreads,
                  boolean asDaemon)

Method Detail

isActive

public boolean isActive()

returns true if at least one thread in the pool is currently active

getNumberOfThreads

public int getNumberOfThreads()

returns the number of all threads currently in this pool

addThread

public int addThread()

adds one ThreadWorker to the pool and returns the current number of threads

idleThreads

public int idleThreads()

returns the number of threads that are currently idle

removeIdleThreads

public int removeIdleThreads()

removes all threads that are currently idle. A thread can only be removed if idle.

Returns:

the number of threads removed

removeIdleThread

public boolean removeIdleThread()

attempts to remove a single ThreadWorker from the pool. If all threads but one have already been removed from the pool, nothing happens and false is returned. This method first attempts to remove an idle thread - if found. If all threads are active, the one with the smallest queue size is removed.

Returns:

true only if a thread was indeed removed from the pool

finishAll

public void finishAll(boolean now)

removes all ThreadWorkers, which will all end either after the current or the last queued task - depending on the 'now' parameter.

getQueueSize

public int getQueueSize()

total queue size over all threads

addListener

public void addListener(ThreadWorker.Listener listener)

getListeners

public ThreadWorker.Listener[] getListeners()

removeListener

public void removeListener(ThreadWorker.Listener listener)

execute

public void execute(Runnable task)

calls runTask(task); this method enables usability with jdk1.5

Specified by:

execute in interface Executor

runTask

public void runTask(Runnable task)
             throws IllegalStateException

Throws:

IllegalStateException