Neil,
Thank you for your answer.
You had right. My mistake was that I was calling modify(fact) each time
after I set the theft assessment.
Best regards,
Oana
Neil Goldman <[EMAIL PROTECTED]> wrote: Oana,
Although your example used a superclass/subclass relationship, the problem
is not due to that relationship, You could just as well have written two CAR
rules :
"if a car's price is <20000, then risk of theft is low"
"if a car has the stealth radar avoidance option, then risk of theft is
high"
You might be upset by the infinite loop, but there is no way to know how you
would like to assess the theft risk of a car that satisfies BOTH conditions.
Here are two ways you might deal with this.
a) maybe neither of these conditions is really sufficient to determine the
theft risk, but simply to influence that risk. The "then" part of the rule
should just increment/decrement a value the accumulates the net risk. But
don't have the increment/decrement also tell drools that the CAR was modified.
b) maybe the rules are TOTALLY ORDERED in your analytical model, and the
first rule that applies is the only one that matters. You can use SALIENCE in
drools to capture ordering. If all the rules are in a single activation group,
then only the highest salience match will actually run (at least, that is my
understanding). Again, you must not tell drools that the CAR has been
modified just because you set its theft assessment.
---------------------------------
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of nicolae oana
Sent: Friday, February 16, 2007 2:11 AM
To: [email protected]
Subject: [rules-users] Subclasses matche superclasses problem.
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
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