[rules-users] how "exists" works exactly?

[Antonio Neto]

Hi,

Thank you very much for all replies.

I've tried also with not ( EPackage(...)), but the result is the same.

I think that I remove the EClass from the facts in my solution, but they
continue in my workingMemory.

How I can see the facts of the workingMemory object (and how remove it)?

Thanks

Best regards

Antonio

2010/5/5 <fgadrat at genigraph.fr>

> Hi Antonio,
> Documentation states that the complement to "not" is "exists", whereas
> "not" keyword is used to match the absence of a fact (in Working Memory),
> and "exists" keyword is used to test the existence of one or more facts (in
> Working memory).
>
> So if you want to test that a fact is not in working memory, then you
> should  use the
> not(MyClass()) pattern.
>
> Hope this helps,
> Francois.
>
> Antonio Neto <antoniosouzaneto at gmail.com> a écrit :
>
>
> > Any idea? Please...
> >
> > 2010/5/4 Antonio Neto <antoniosouzaneto at gmail.com>
> >
> >> Hi all,
> >>
> >> I don't know exactly why I have a problem in my "exists" function. I've
> >> tried many different ways, but it does not work. Anybody could help me,
> >> please?
> >>
> >>
> >> I have the following rules:
> >>
> >> *rule "diff"
> >> when
> >>     $var1: EReference(name == "employee")
> >>     $var2: EClass(name == "Company", EAllReferences contains $var1)
> >>     not (exists( EPackage(EClassifiers contains $var2 ) ))
> >> then
> >>     insertLogical(new IntConstraintOccurrence("diff", 10));
> >> end
> >>
> >> rule "ClassesNotReferenced"
> >>     when
> >>         $q1 : EClass();
> >>         $q2 : EPackage(EClassifiers contains $q1);
> >>         not( exists ( EReference(EType == $q1) ));
> >>     then
> >>         insertLogical(new
> IntConstraintOccurrence("ClassesNotReferenced",
> >> 1, $q1));
> >> end*
> >>
> >>
> >> and in my facts (and my EPackage) I have 4 instances of EClass "Company"
> >> with a EReference "employee", and another EClass "Person".  I still have
> a
> >> "move" that removes EClasses in my Drools Solver.
> >>
> >> I need to have only one classe "Company" after processing. But it
> removes
> >> only the EClass "Person", when it was supposed to remove one EClass
> "Person"
> >> and 3 ECLasses "Company". Leaving one EClass "Company" in the end.
> >>
> >> The problem is:  when Drools tries to remove a EClass "Person" it thinks
> >> that  the EClass "Company" does not exists. But in fact there are 3
> others.
> >>
> >> Any clue about it, please ?
> >>
> >> Thanks
> >>
> >> Bests regards
> >>
> >> Antonio
> >>
> >>
> >>
> >
>
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