edu.jas.util
Class ThreadPool

java.lang.Object
  edu.jas.util.ThreadPool

public class ThreadPool
extends java.lang.Object

Thread pool using stack / list workpile.

Author:

Akitoshi Yoshida, Heinz Kredel

Field Summary

protected int	idleworkers Number of idle workers.
protected java.util.LinkedList<java.lang.Runnable>	jobstack Work queue / stack.
protected boolean	shutdown Shutdown request.
protected StrategyEnumeration	strategy
protected edu.jas.util.PoolThread[]	workers Array of workers.

Constructor Summary

ThreadPool()
Constructs a new ThreadPool with strategy StrategyEnumeration.FIFO and size DEFAULT_SIZE.

ThreadPool(int size)
Constructs a new ThreadPool with strategy StrategyEnumeration.FIFO.

ThreadPool(StrategyEnumeration strategy)
Constructs a new ThreadPool with size DEFAULT_SIZE.

ThreadPool(StrategyEnumeration strategy, int size)
Constructs a new ThreadPool.

Method Summary

void	addJob(java.lang.Runnable job) adds a job to the workpile.
int	cancel() Cancels the threads.
protected java.lang.Runnable	getJob() get a job for processing.
int	getNumber() number of worker threads.
StrategyEnumeration	getStrategy() get used strategy.
boolean	hasJobs() check if there are jobs for processing.
boolean	hasJobs(int n) check if there are more than n jobs for processing.
void	init() thread initialization and start.
void	terminate() Terminates the threads.
java.lang.String	toString() toString.

Methods inherited from class java.lang.Object

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

Field Detail

workers

protected edu.jas.util.PoolThread[] workers

Array of workers.

idleworkers

protected int idleworkers

Number of idle workers.

shutdown

protected volatile boolean shutdown

Shutdown request.

jobstack

protected java.util.LinkedList<java.lang.Runnable> jobstack

Work queue / stack.

strategy

protected StrategyEnumeration strategy

Constructor Detail

ThreadPool

public ThreadPool()

Constructs a new ThreadPool with strategy StrategyEnumeration.FIFO and size DEFAULT_SIZE.

ThreadPool

public ThreadPool(StrategyEnumeration strategy)

Constructs a new ThreadPool with size DEFAULT_SIZE.

Parameters:

strategy - for job processing.

ThreadPool

public ThreadPool(int size)

Constructs a new ThreadPool with strategy StrategyEnumeration.FIFO.

Parameters:

size - of the pool.

ThreadPool

public ThreadPool(StrategyEnumeration strategy,
                  int size)

Constructs a new ThreadPool.

Parameters:

strategy - for job processing.

size - of the pool.

Method Detail

init

public void init()

thread initialization and start.

toString

public java.lang.String toString()

toString.

Overrides:

toString in class java.lang.Object

getNumber

public int getNumber()

number of worker threads.

getStrategy

public StrategyEnumeration getStrategy()

get used strategy.

terminate

public void terminate()

Terminates the threads.

cancel

public int cancel()

Cancels the threads.

addJob

public void addJob(java.lang.Runnable job)

adds a job to the workpile.

Parameters:

job -

getJob

protected java.lang.Runnable getJob()
                             throws java.lang.InterruptedException

get a job for processing.

Throws:

java.lang.InterruptedException

hasJobs

public boolean hasJobs()

check if there are jobs for processing.

hasJobs

public boolean hasJobs(int n)

check if there are more than n jobs for processing.

Parameters:

n - Integer

Returns:

true, if there are possibly more than n jobs.