Java Doc for TimeScheduler.java in  » Net » JGroups-2.4.1-sp3 » org » jgroups » util » Java Source Code / Java DocumentationJava Source Code and Java Documentation

The scheduler supports varying scheduling intervals by asking the task every time for its next preferred scheduling interval. Scheduling can either be fixed-delay or fixed-rate. The notions are borrowed from java.util.Timer and retain the same meaning. I.e. in fixed-delay scheduling, the task's new schedule is calculated as:
new_schedule = time_task_starts + scheduling_interval

In fixed-rate scheduling, the next schedule is calculated as:
new_schedule = time_task_was_supposed_to_start + scheduling_interval

The scheduler internally holds a queue of tasks sorted in ascending order according to their next execution time. A task is removed from the queue if it is cancelled, i.e. if TimeScheduler.Task.isCancelled() returns true.

The scheduler internally uses a java.util.SortedSet to keep tasks sorted. java.util.Timer uses an array arranged as a binary heap that doesn't shrink. It is likely that the latter arrangement is faster.

Initially, the scheduler is in SUSPENDed mode, start() need not be called: if a task is added, the scheduler gets started automatically. Calling start() starts the scheduler if it's suspended or stopped else has no effect. Once stop() is called, added tasks will not restart it: start() has to be called to restart the scheduler.
author:
   Bela Ban
version:
   $Id: TimeScheduler.java,v 1.14.2.2 2007/04/27 09:11:18 belaban Exp $

true:
Task is rescheduled relative to the last time it actuallystarted execution

false:
Task is scheduled relative to its last execution schedule.

true:
Task is rescheduled relative to the last time it actuallystarted execution

false:
Task is scheduled relative to its last execution schedule. Thishas the effect that the time between two consecutive executions ofthe task remains the same.

April 07: the relative argument is ignored, will always be true