Class Scheduler

java.lang.Object

java.lang.Thread

org.apache.log4j.scheduler.Scheduler

All Implemented Interfaces:

Runnable

public class Scheduler
extends Thread

A simple but still useful implementation of a Scheduler (in memory only).

This implementation will work very well when the number of scheduled job is small, say less than 100 jobs. If a larger number of events need to be scheduled, than a better adapted data structure for the jobList can give improved performance.

Author:

Ceki

Nested Class Summary

Nested classes/interfaces inherited from class Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor	Description
Scheduler()	Create new instance.

Method Summary

Modifier and Type	Method	Description
boolean	changePeriod(Job job, long newPeriod)	Change the period of a job.
boolean	delete(Job job)	Delete the given job.
void	run()	Run scheduler.
void	schedule(Job job, long desiredTime)	Schedule a Job for execution at system time given by the desiredTime parameter.
void	schedule(Job job, long desiredTime, long period)	Schedule a Job for execution at system time given by the desiredTime parameter.
void	shutdown()	Shut down scheduler.

Methods inherited from class Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, onSpinWait, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class Object

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

Constructor Details

Scheduler

public Scheduler()

Create new instance.

Method Details

delete

public boolean delete(Job job)

Delete the given job.

Parameters:

job - job.

Returns:

true if the job could be deleted, and false if the job could not be found or if the Scheduler is about to shutdown in which case deletions are not permitted.

schedule

public void schedule(Job job,
 long desiredTime)

Schedule a Job for execution at system time given by the desiredTime parameter.

Parameters:

job - job to schedule.

desiredTime - desired time of execution.

schedule

public void schedule(Job job,
 long desiredTime,
 long period)

Schedule a Job for execution at system time given by the desiredTime parameter.

The job will be rescheduled. It will execute with a frequency determined by the period parameter.

Parameters:

job - job to schedule.

desiredTime - desired time of execution.

period - repeat period.

changePeriod

public boolean changePeriod(Job job,
 long newPeriod)

Change the period of a job. The original job must exist for its period to be changed.

The method returns true if the period could be changed, and false otherwise.

Parameters:

job - job.

newPeriod - new repeat period.

Returns:

true if period could be changed.

shutdown

public void shutdown()

Shut down scheduler.

run

public void run()

Run scheduler.

Specified by:

run in interface Runnable

Overrides:

run in class Thread