edu.ull.cgunay.utils
Class ParallelTask

java.lang.Object
  |
  +--edu.ull.cgunay.utils.ParallelTask

All Implemented Interfaces:

Serializable, Simulation

public class ParallelTask

extends Object

implements Simulation

Parallel analog of an iteration where a given task is executed on each of the items of a collection concurrently. The init() method creates threads for all items and the step() method contains the synchronization algorithm required to start and end all tasks concurrently. stop() terminates all threads and therefore relinquishes resources.

Subsequent calls to step() is mutually exclusive by ensuring that the the new step does not start until the previous step is completed.

TODO: Make it more expressive.

Version:

$Revision: 1.6 $ for this file

Author:

Cengiz Gunay

See Also:

Iteration, Serialized Form

Field Summary

Collection	collection The collection on which to iterate.
int	runcount Semaphore for threads that are running.
(package private) Task	task Task to be executed at each step by each thread.
(package private) ThreadGroup	threads Group together the threads in order to terminate them at once.
int	waitcount Semaphore for threads that are waiting.

Constructor Summary

ParallelTask(Collection collection, Task task)
Set collection and task.

Method Summary

void	init() Start a new thread containing the Objective runnable for each element in the collection.
void	reset() Resets value of runcount to max # of threads.
void	step() Does the following: Wait for all threads to go in wait() (until waitcount = max) Notify all of them, therefore make them execute the task.
void	stop() Terminates all threads, presumably releasing all resources.

Methods inherited from class java.lang.Object

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

Field Detail

collection

public Collection collection

The collection on which to iterate.

waitcount

public volatile int waitcount

Semaphore for threads that are waiting.

runcount

public volatile int runcount

Semaphore for threads that are running.

task

Task task

Task to be executed at each step by each thread.

threads

ThreadGroup threads

Group together the threads in order to terminate them at once.

Constructor Detail

ParallelTask

public ParallelTask(Collection collection,
                    Task task)

Set collection and task.

Parameters:

collection - a Collection value

task - a Task value

Method Detail

reset

public void reset()

Resets value of runcount to max # of threads.

init

public void init()

Start a new thread containing the Objective runnable for each element in the collection.

Specified by:

init in interface Simulation

See Also:

Objective

step

public void step()

Does the following:

1. Wait for all threads to go in wait() (until waitcount = max)
2. Notify all of them, therefore make them execute the task.
3. Wait for all of the to finish (until runcount == 0).

   Specified by:

   step in interface Simulation

stop

public void stop()

Terminates all threads, presumably releasing all resources.

Specified by:

stop in interface Simulation