[rules-users] Problem using 'not contains'

[Greg Barton]

It must be another factor.  In the attached code, the rule only fires once, as it should. (Using drools 5) 

Allen, are your equals/hashCode methods for Satellite consistent?  A problem in those could cause this kind of behavior.  The ones in the attached code are generated from eclipse.  They're overkill, but always work well. :)

--- On Mon, 4/20/09, Edson Tirelli <tirelli at post.com> wrote:

> From: Edson Tirelli <tirelli at post.com>
> Subject: Re: [rules-users] Problem using 'not contains'
> To: "Rules Users List" <rules-users at lists.jboss.org>
> Date: Monday, April 20, 2009, 6:16 PM
> Allen,
> 
>    I am not sure what is happening, because the correct way
> is to call a
> modify/update on $sm:
> 
> when
>     $sat : Satellite(isOverhead == true)
>     $sm : SatManager($ls : listOfOverheadSats not contains
> $sat)
> then
>     $ls.add($sat);
>     update( $sm );
> end
> 
>    This should not loop because of the condition itself,
> since now the "not
> contains" condition will be false and will prevent the
> loop.
> 
>    Can you double check there isn't another rule that
> is causing the loop?
> Otherwise, please open a JIRA.
> 
>    Regarding the question, drools manages collections as
> attributes in the
> same way it manages any other kind of "Object"
> attribute. Although, in
> drools 4, shadow facts do a shallow copy on collection
> attributes that
> sometimes require some care when working with evals(). But
> this is not your
> case.
> 
>     []s
>     Edson
> 
> 
> 
> 2009/4/20 Bagwell, Allen F <afbagwe at sandia.gov>
> 
> >
> > 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.
> >
> >
> >
> > _______________________________________________
> > rules-users mailing list
> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
> >
> 
> 
> -- 
>  Edson Tirelli
>  JBoss Drools Core Development
>  JBoss, a division of Red Hat @ www.jboss.com
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users


      
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