org.quartz.simpl

Class ZeroSizeThreadPool

java.lang.Object

org.quartz.simpl.ZeroSizeThreadPool

All Implemented Interfaces:

ThreadPool

public class ZeroSizeThreadPool
extends java.lang.Object
implements ThreadPool

This is class is a simple implementation of a zero size thread pool, based on the ThreadPool interface.

The pool has zero Threads and does not grow or shrink based on demand. Which means it is obviously not useful for most scenarios. When it may be useful is to prevent creating any worker threads at all - which may be desirable for the sole purpose of preserving system resources in the case where the scheduler instance only exists in order to schedule jobs, but which will never execute jobs (e.g. will never have start() called on it).

Author:

Wayne Fay

Constructor Summary

Constructors

Constructor and Description
ZeroSizeThreadPool() Create a new ZeroSizeThreadPool.

Method Summary

Methods

Modifier and Type	Method and Description
int	blockForAvailableThreads() Determines the number of threads that are currently available in in the pool.
org.apache.commons.logging.Log	getLog()
int	getPoolSize()
void	initialize() Called by the QuartzScheduler before the ThreadPool is used, in order to give the it a chance to initialize.
boolean	runInThread(java.lang.Runnable runnable) Execute the given Runnable in the next available Thread.
void	shutdown()
void	shutdown(boolean waitForJobsToComplete) Called by the QuartzScheduler to inform the ThreadPool that it should free up all of it's resources because the scheduler is shutting down.

Methods inherited from class java.lang.Object

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

Constructor Detail

ZeroSizeThreadPool

public ZeroSizeThreadPool()

Create a new ZeroSizeThreadPool.

Method Detail

getLog

public org.apache.commons.logging.Log getLog()

getPoolSize

public int getPoolSize()

Specified by:

getPoolSize in interface ThreadPool

initialize

public void initialize()
                throws SchedulerConfigException

Description copied from interface: ThreadPool

Called by the QuartzScheduler before the ThreadPool is used, in order to give the it a chance to initialize.

Specified by:

initialize in interface ThreadPool

Throws:

SchedulerConfigException

shutdown

public void shutdown()

shutdown

public void shutdown(boolean waitForJobsToComplete)

Description copied from interface: ThreadPool

Called by the QuartzScheduler to inform the ThreadPool that it should free up all of it's resources because the scheduler is shutting down.

Specified by:

shutdown in interface ThreadPool

runInThread

public boolean runInThread(java.lang.Runnable runnable)

Description copied from interface: ThreadPool

Execute the given Runnable in the next available Thread.

The implementation of this interface should not throw exceptions unless there is a serious problem (i.e. a serious misconfiguration). If there are no immediately available threads false should be returned.

Specified by:

runInThread in interface ThreadPool

Returns:

true, if the runnable was assigned to run on a Thread.

blockForAvailableThreads

public int blockForAvailableThreads()

Description copied from interface: ThreadPool

Determines the number of threads that are currently available in in the pool. Useful for determining the number of times runInThread(Runnable) can be called before returning false.

The implementation of this method should block until there is at least one available thread.

Specified by:

blockForAvailableThreads in interface ThreadPool

Returns:

the number of currently available threads