com.iplanet.am.util

Class ThreadPool

java.lang.Object

com.iplanet.am.util.ThreadPool

public class ThreadPool
extends Object

This thread pool maintains a number of threads that run the tasks from a task queue one by one. The tasks are handled in asynchronous mode, which means it will not block the main thread to proceed while the task is being processed by the thread pool.

This thread pool has a fixed size of threads. It maintains all the tasks to be executed in a task queue. Each thread then in turn gets a task from the queue to execute. If the tasks in the task queue reaches a certain number(the threshold value), it will log an error message and ignore the new incoming tasks until the number of un-executed tasks is less than the threshold value. This guarantees the thread pool will not use up the system resources under heavy load.

Constructor Summary

Constructors

Constructor and Description
ThreadPool(String name, int poolSize, int threshold, boolean daemon, Debug debug) Constructs a thread pool with given parameters.

Method Summary

Modifier and Type	Method and Description
protected void	createThreads(int threadsToCreate) Create thread for the pool.
protected void	deductCurrentThreadCount()
int	getCurrentSize()
int	getCurrentThreadCount()
protected void	returnThread(com.iplanet.am.util.ThreadPool.WorkerThread t)
void	run(Runnable task) Runs a user defined task.
void	shutdown()

Methods inherited from class java.lang.Object

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

Constructor Detail

ThreadPool

public ThreadPool(String name,
                  int poolSize,
                  int threshold,
                  boolean daemon,
                  Debug debug)

Constructs a thread pool with given parameters.

Parameters:

name - name of the thread pool.

poolSize - the thread pool size, indicates how many threads are created in the pool.

threshold - the maximum size of the task queue in the thread pool.

daemon - set the threads as daemon if true; otherwise if not.

debug - Debug object to send debugging message to.

Method Detail

createThreads

protected void createThreads(int threadsToCreate)

Create thread for the pool.

Parameters:

threadsToCreate - number of threads of the pool after creation

run

public final void run(Runnable task)
               throws ThreadPoolException

Runs a user defined task.

Parameters:

task - user defined task.

Throws:

ThreadPoolException

deductCurrentThreadCount

protected void deductCurrentThreadCount()

returnThread

protected void returnThread(com.iplanet.am.util.ThreadPool.WorkerThread t)

shutdown

public void shutdown()

getCurrentThreadCount

public int getCurrentThreadCount()

getCurrentSize

public int getCurrentSize()