Asynchronous Events and Handlers - Revision history

Suhridk: /* RTSJ Approach */

2012-01-10T18:42:59Z

RTSJ Approach

Suhridk at 13:24, 9 January 2012

2012-01-09T13:24:53Z

Suhridk: /* RTSJ Approach */

2012-01-01T20:27:47Z

RTSJ Approach

Suhridk at 14:09, 1 January 2012

2012-01-01T14:09:06Z

Suhridk: /* Intro */

2012-01-01T03:02:44Z

Intro

Suhridk: /* RTSJ Approach */

2012-01-01T02:37:16Z

RTSJ Approach

Suhridk: /* RTSJ Approach */

2012-01-01T02:16:36Z

RTSJ Approach

Suhridk: /* RTSJ Approach */

2012-01-01T02:15:20Z

RTSJ Approach

Suhridk: /* Intro */

2012-01-01T02:07:06Z

Intro

Suhridk: Created page with "= Intro = * Interaction between real world object and their controllers can be time triggered or event triggered. * Category:RealtimeJava"

2012-01-01T01:04:43Z

Created page with "= Intro = * Interaction between real world object and their controllers can be time triggered or event triggered. * Category:RealtimeJava"

New page

= Intro =

* Interaction between real world object and their controllers can be time triggered or event triggered.
*

[[Category:RealtimeJava]]

@@ Line 20: / Line 20: @@
 * Provides real time Asynchronous Events (AE's) and associated handlers (AEH).
-* AE's are data less and are fired by the program or associated with occurrence of interrupts in the environment.
+* AE's are data less happening and are fired by the program or associated with occurrence of interrupts in the environment.
 * Association betwen AE's and AEH's is dynamic. 1 AE can have many AEH. 1 AEH can be for many AEs.
 * Each AEH has a count of fired events, When an event is fired, counter is '''atomically''' incremented.

← Older revision		Revision as of 13:24, 9 January 2012
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	* Timer is flexible, it can be enabled, disabled, rescheduled.		* Timer is flexible, it can be enabled, disabled, rescheduled.

−	[[Category:~~RealTimeJava~~]]	+	[[Category:RealtimeJava]]

@@ Line 23: / Line 23: @@
 * Association betwen AE's and AEH's is dynamic. 1 AE can have many AEH. 1 AEH can be for many AEs.
 * Each AEH has a count of fired events, When an event is fired, counter is '''atomically''' incremented.
 * The handler is then '''released.'''

← Older revision		Revision as of 14:09, 1 January 2012
Line 86:		Line 86:
	* Timer is flexible, it can be enabled, disabled, rescheduled.		* Timer is flexible, it can be enabled, disabled, rescheduled.

−	[[Category:~~RealtimeJava~~]]	+	[[Category:RealTimeJava]]

@@ Line 12: / Line 12: @@
 * Alternative is Event based programming.
 * Each event has an associated handler, events are queued and their associated handler is executed.
-* No need for communication among handlers as they can read/write from shared objects. [TODO]
+* No need for communication among handlers as they can read/write from shared objects.
 * Disadvantage:
 ** Difficult to have tight DL's as long lived and non blocking handler must finish before a high priority handler can be executed.
-** Difficult to execute handlers on a multiprocessor system as handlers assume no contention for shared resources. [TODO]
+** Difficult to execute handlers on a multiprocessor system as handlers assume no contention for shared resources. Since handlers cannot execute simultaneously like threads.
 = RTSJ Approach =

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 * This has some overhead, so time critical AEH's can bind themself to a dedicated real time thread.
 * This is done by using a BoundAsyncEventHandler object which is a subclass of AsyncEventHandler.
 [[Category:RealtimeJava]]

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 * ASEH itself has a run() method which is called by system when AE is fired. So run() internally calls handleAsyncEvent() repeatedly whenever fireCount > 0.
 * Example:
 <syntaxhighlight lang="java5">

← Older revision		Revision as of 02:15, 1 January 2012
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	</syntaxhighlight>		</syntaxhighlight>

		+	* Both RT Thread's and AEH's are Schedulable objects.
		+	* In practice, RTT's are vehicles for AEH's.
		+	* An AEH is bound to a server RT Thread - this is done dynamically.
		+	* This has some overhead, so time critical AEH's can bind themself to a dedicated real time thread.
		+	* This is done by using a BoundAsyncEventHandler object which is a subclass of AsyncEventHandler.

	[[Category:RealtimeJava]]		[[Category:RealtimeJava]]

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 * Interaction between real world object and their controllers can be time triggered or event triggered.
+* In a time triggered system controller activates periodically to check status of object.
 [[Category:RealtimeJava]]