Re: [rules-users] Subclasses matche superclasses problem.
Hi Oana,
On 2/16/07, nicolae oana <oananicolae1981(a)yahoo.com> wrote:
Hi everybody,
I have a class Car which is superclass for class ConvertibleCar, two rules
(described below) and a ConvertibleCar fact in working memory that causes
both rules to fire, resulting this way an unwanted change to the car`s
attribute and an infinite loop.
How do I evitate this problem: the specialization class fact to not match
its superclass column in a rule?
ConvertibleCar car =new ConvertibleCar(10000);
rule "rule-1"
when
$car:Convertible()
then
$car.setPotentialTheftRating("high");
end
rule "rule-2"
when
$car:Car(price<20000)
then
$car.setPotentialTheftRating("low");
end
Best regards, Oana
I'd say that this behaviour is correct in principle. If you want to
avoid this, you could add further constraints in the rules concerning
the superclass:
rule "rule-2"
when
$car:Car(price<20000, class != Convertible.class)
then
$car.setPotentialTheftRating("low");
end
I'm not sure if this works exactly like that (don't have a Drools
installation at hand), but I guess you get the idea.
Best regards
Marcus