[rules-users] "not" combined with predicate?

[Edson Tirelli]

   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
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> rules-users at lists.jboss.org
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>


-- 
 Edson Tirelli
 Software Engineer - JBoss Rules Core Developer
 Office: +55 11 3124-6000
 Mobile: +55 11 9218-4151
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