[rules-users] Accumulator being executed depending on the number of events

[Wolfgang Laun]

On 21/06/2012, ekzl at yahoo.com <ekzl at yahoo.com> wrote:
> Hi,
>
> I'm experimenting with Drools and have troubles understanding the way
> accumulators work. Before i go and look at the source code i was wondering
> if the way the accumulators work is designed as described below or of it
> has
> something to do with my rules configuration.
>
> I'm using drools distibution 5.4.0. So this is my test case:
>
> I have 3 similar events and 1 rule containing an accumulator. So when
> firing
> the alerts obviously as the events are similar the same rule is fired. So
> accorrding to me when the rule is fired drools creates a new accumulator

This isn't true. A new Context is created.


> and
> passed data for all events

Correct.

> but at the same time the first accumulator still
> exists
No.

> and receives only the datza for the second event. The 3rd event will
> trigger accumulate for context1 and context2 and then create a new
> accumulator with all the 3 events. This results in actually having 3
> accumulators with exactly the same data.

No.
>
> I have created a dummy accumulator to test this:
>
> Here is the DRL
>
> rule "update profile"
>   salience 1000 // Make sure this rule is always executed by giving it a
> very high salience
>   no-loop true
> when
> 	$event: TestEvent()
> 	$profile: Profile( key == $event.key)
> 	$total : Number() from accumulate( TestEvent( $p : value, key ==
> $event.key), test( $p ) )	
> then
> 	System.out.println("Total:" + $total);
> end
>
>
>
>
> Here is the output
>
> Event 1
>   Context created:137
>   Init called for context:137
>   accumulate called for context:137 object:80
>   Total called for context:137
>   Total:80
>
> Event 2
> Context created:858
> Init called for context:858
> accumulate called for context:858 object:80
> Total called for context:858
> accumulate called for context:137 object:41
> accumulate called for context:858 object:41
> Total called for context:858
> Total called for context:137
> Total:121
> Total:121
>
> Event 3
> Context created:724
> Init called for context:724
> accumulate called for context:724 object:80
> accumulate called for context:724 object:41
> Total called for context:724
> accumulate called for context:137 object:53
> accumulate called for context:858 object:53
> accumulate called for context:724 object:53
> Total called for context:724
> Total called for context:858
> Total called for context:137
> Total:174
> Total:174
> Total:174
>
>
> How can i remove the accumulator after the rule is finished?
>

You don't have to.

-W


> Regards,
> e
>
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