Re: [rules-users] "not" combined with predicate?
Thanks for the feedback.
Assuming I really have a null somewhere (rather than a drools bug),
how would I go about debugging this? Since the crash occurs in the
rule class generated at runtime, I cannot set a breakpoint to look at
which values might be null. Any advice on this?
Thanks,
-Chris West
On 2/21/07, Edson Tirelli <tirelli(a)post.com> wrote:
Chris,
The following must work just fine:
Person( girlAge : age, sex = "F" )
not Person( boyAge : age -> ( girlAge.intValue() == boyAge.intValue() +
2 ), sex = 'M' )
The only reason I can see for that to fail is if age is an object
type attribute (Integer, Double, etc) and it is set to null. Otherwise,
it is probably a bug.
Bellow is not supposed to work:
Person( girlAge : age, sex = "F" )
not Person( boyAge : age, sex = 'M' )
eval ( girlAge.intValue() == boyAge.intValue() + 2 )
The reason is because "not" means you DON'T have a Person object
with that attributes (the boy), so you can't eval anything using "boyAge".
[]s
Edson
Chris West wrote:
> Does anyone know if there is a problem using a "not" combined with a
> predicate expression? Drools gives me a NullPointerException
> sometimes when evaluating my predicate. The example from the user
> guide is:
>
> Person( girlAge : age, sex = "F" )
> Person( boyAge : age -> ( girlAge.intValue() == boyAge.intValue() + 2
> ), sex = 'M' )
>
> Buy I'm trying something similar to:
>
> Person( girlAge : age, sex = "F" )
> not Person( boyAge : age -> ( girlAge.intValue() == boyAge.intValue()
> + 2 ), sex = 'M' )
>
> And also:
>
> Person( girlAge : age, sex = "F" )
> not Person( boyAge : age, sex = 'M' )
> eval ( girlAge.intValue() == boyAge.intValue() + 2 )
>
> Is there anything wrong with these? The compiler does not have a
> problem with the former, but does not like the latter. I'm using
> Drools 3.0.5. I'm basically trying to say "there is a girl, and there
> is not a boy whose age is 2 years less than the girl".
>
> Any thoughts on this would be greatly appreciated.
>
> Thanks,
> -Chris West
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
--
Edson Tirelli
Software Engineer - JBoss Rules Core Developer
Office: +55 11 3124-6000
Mobile: +55 11 9218-4151
JBoss, a division of Red Hat @ www.jboss.com
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