[rules-users] Problem using 'not contains'

[Ingomar Otter]

I would be intrested in the "how does Drools manage its knowledge of  
changes to Collections embedded in fact objects" question as well.  
That caused some headache earlier this year we never got to the bottom  
of the behaviour and in the end worked around it in not-so-elegant ways.


Am 20.04.2009 um 18:31 schrieb Bagwell, Allen F:

>
> This is in Drools 4.0.7
>
> I have a class called SatManager with a field:
>
> ArrayList<Satellite> listOfOverheadSats
>
> That has an appropriate getter method.
>
> I have a relatively simple rule that goes something like this:
>
> when
>    $sat : Satellite(isOverhead == true)
>    $sm : SatManager($ls : listOfOverheadSats not contains $sat)
> then
>    $ls.add($sat);
>
> My problem is that Drools doesn't understand that the ArrayList has  
> been modified, therefore this rule always fires on the same  
> satellite if the sat object changes in any other way.
>
> I've tried adding:
>
> update($sm);
>
> To the consequence, but that only caused the rule to re-fire  
> infinitely -- even with the no-loop keyword applied.
>
> So my question is how does Drools manage its knowledge of changes to  
> Collections embedded in fact objects? The documention for the  
> 'contains/not contains' keyword did not explain this.
>
> I'm really stumped here.
>
> Allen F. Bagwell
> e-mail:  afbagwe at sandia.gov
> phone:  505/284-4517
> fax:  505/ 844-7886
>
>
> Ask your doctor if medical advice from a TV commercial is right for  
> you.
>
>
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