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

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(a)gmail.com&gt; a écrit : > Any idea? Please... > > 2010/5/4 Antonio Neto <antoniosouzaneto(a)gmail.com&gt; > >> 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 >> >> >> > _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users