Scheduled-task pattern: Difference between revisions

Revision as of 21:05, 3 January 2003

Revision as of 21:06, 3 January 2003

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The '''scheduled- task pattern''' is a software [[design pattern]] used in [[software engineering]]. It is used to ensure that desired operations are performed at specific points in the future.

In RealTime[[Real-time]] [[Computer software|systems]], it is often necessary to ensure that something is done at a specific time. A scheduler object (note: not quite the same as SchedulerPattern[[scheduler pattern]]) keeps track of these actions, and invokes them at the appropriate times.

'''Intent:''' Ensure that desired operations are performed at specific points in the future.

In RealTime systems, it is often necessary to ensure that something is done at a specific time. A scheduler object (note: not quite the same as SchedulerPattern) keeps track of these actions, and invokes them at the appropriate times.

Times may be expressed as "wall time" or as some sort of internal time ("ticks", milliseconds-since-startup, etc.).

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If highly accurate scheduling of tasks is needed (to milliseconds or less), the scheduler task needs to run at a very high priority, or be hooked into a high-frequency interrupt routine.

'''See also:''' [[Command pattern]], [[Memento pattern]]

''Is there another, more common name for this pattern?''

'''See also:''' CommandPattern, MementoPattern

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== External Link ==

The PPR has MartinFowler's "Recurring Events" document at http://c2.com/ppr/schedule.pdf

The PPR has MartinFowler's "''Recurring Events"'' document at PPR: http://c2.com/ppr/schedule.pdf

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CategoryPattern | CategoryBehavioralPatterns | CategoryRealTimePatterns