jsat.utils

Class PoisonRunnable

java.lang.Object

jsat.utils.PoisonRunnable

All Implemented Interfaces:

Runnable

public final class PoisonRunnable
extends Object
implements Runnable

A helper class for using the reader / writer model to implement parallel algorithms. When using the a BlockingQueue, null is an invalid value. However, if several threads have been started that are simply reading from the queue for jobs, we want to let the threads know when to stop. Polling can not be used since the BlockingQueue.take() operations blocks until a value is added. If the queue is a queue of Runnable jobs, this class solves the problem. An instanceof check can be done on the returned runnable. If it is a poisoned one, the worker knows to stop consuming and terminate.

By default, the run() method does not perform any action. The poison runnable can be used to perform ending clean up work, such as posting to a semaphore, by giving the work job to the PoisonRunnable(java.lang.Runnable) constructor. The runnable given will be run when the Poison runnable's run method is called.

Author:

Edward Raff

Constructor Summary

Constructors

Constructor and Description
PoisonRunnable() Creates a new PoisonRunnable that will do nothing when its run method is called.
PoisonRunnable(CountDownLatch latch) Creates a new PoisonRunnable that will call the CountDownLatch.countDown() method on the given latch when its run method is finally called.
PoisonRunnable(CyclicBarrier barrier) Creates a new PoisonRunnable that will call the CyclicBarrier.await() method of the given barrier when its run method is finally called.
PoisonRunnable(Runnable lastStep) Creates a new PoisonRunnable that will run the given runnable when it is called.

Method Summary

Modifier and Type	Method and Description
void	run()

Methods inherited from class java.lang.Object

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

Constructor Detail

PoisonRunnable

public PoisonRunnable(Runnable lastStep)

Creates a new PoisonRunnable that will run the given runnable when it is called.

Parameters:

lastStep - the runnable to call when this runnable is finally called.

PoisonRunnable

public PoisonRunnable(CountDownLatch latch)

Creates a new PoisonRunnable that will call the CountDownLatch.countDown() method on the given latch when its run method is finally called.

Parameters:

latch - the latch to decrement

PoisonRunnable

public PoisonRunnable(CyclicBarrier barrier)

Creates a new PoisonRunnable that will call the CyclicBarrier.await() method of the given barrier when its run method is finally called.

Parameters:

barrier - the barrier to wait on.

PoisonRunnable

public PoisonRunnable()

Creates a new PoisonRunnable that will do nothing when its run method is called.

Method Detail

run

public void run()

Specified by:

run in interface Runnable