net.sf.basedb.util.timer
Class Scheduler

java.lang.Object
  net.sf.basedb.util.timer.Scheduler

public class Scheduler
extends Object

This class is a cousin to the standard Timer class but only allows scheduling of tasks. This allows an application to create a core timer and let other code add TimerTask:s to the timer.

Another feature of this class is that it can force the execution of tasks in their own threads. This avoids that long-runing tasks hog the timer thread and therby prevent other tasks from running.

If new threads are created for the tasks, it is also possible to specify on a task-by-task basis if the task may run in multiple threads at the same time.

A side-effect by using a scheduler is that all methods may return a different TimerTask object than what was scheduled. If the calling application want to cancel a task it must do so on the object that is returned, since that object is the one really lives in the timer. However, calling TimerTask.cancel() passes through to the original task as well.

Version:

2.0

Author:

nicklas

See Also:

Timer, TimerTask, ThreadTimerTask

Last modified

$Date: 2008-09-11 22:08:14 +0200 (Thu, 11 Sep 2008) $

Field Summary

private boolean	newThreads
private Timer	timer

Constructor Summary

Scheduler(Timer timer, boolean newThreads)
Create a new scheduler object.

Method Summary

private TimerTask	getTimerTask(TimerTask task, boolean allowMultiple)
TimerTask	schedule(TimerTask task, Date time, boolean allowMultiple)
TimerTask	schedule(TimerTask task, Date firstTime, long period, boolean allowMultiple)
TimerTask	schedule(TimerTask task, long delay, boolean allowMultiple)
TimerTask	schedule(TimerTask task, long delay, long period, boolean allowMultiple)
TimerTask	scheduleAtFixedRate(TimerTask task, Date firstTime, long period, boolean allowMultiple)
TimerTask	scheduleAtFixedRate(TimerTask task, long delay, long period, boolean allowMultiple)

Methods inherited from class java.lang.Object

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

Field Detail

timer

private final Timer timer

newThreads

private final boolean newThreads

Constructor Detail

Scheduler

public Scheduler(Timer timer,
                 boolean newThreads)

Create a new scheduler object.

Parameters:

timer - The underlying timer object which handles the execution of the tasks

newThreads - If TRUE, each task is started in it's own thread, if FALSE the tasks are executed in the timers thread

Method Detail

getTimerTask

private TimerTask getTimerTask(TimerTask task,
                               boolean allowMultiple)

schedule

public TimerTask schedule(TimerTask task,
                          Date time,
                          boolean allowMultiple)

See Also:

Timer.schedule(TimerTask, Date)

schedule

public TimerTask schedule(TimerTask task,
                          Date firstTime,
                          long period,
                          boolean allowMultiple)

See Also:

Timer.schedule(TimerTask, Date, long)

schedule

public TimerTask schedule(TimerTask task,
                          long delay,
                          boolean allowMultiple)

See Also:

Timer.schedule(TimerTask, long)

schedule

public TimerTask schedule(TimerTask task,
                          long delay,
                          long period,
                          boolean allowMultiple)

See Also:

Timer.schedule(TimerTask, long, long)

scheduleAtFixedRate

public TimerTask scheduleAtFixedRate(TimerTask task,
                                     Date firstTime,
                                     long period,
                                     boolean allowMultiple)

See Also:

Timer.scheduleAtFixedRate(TimerTask, Date, long)

scheduleAtFixedRate

public TimerTask scheduleAtFixedRate(TimerTask task,
                                     long delay,
                                     long period,
                                     boolean allowMultiple)

See Also:

Timer.scheduleAtFixedRate(TimerTask, long, long)