[rules-users] Ask for help on rule authoring

[Michael Anstis]

I'd assume you set "null" as a literal value on the rule?

There's sort of a problem, AFAIK, that all literals are escaped as String in
the RHS of a rule.

You might be best suited to electing to use "New Formula" and specifying the
text "age ==null || age.size() == 0".

This generates an inline eval for your constraint, which although not
optimal, should work.

With kind regards,

Mike

2011/3/25 Wolfgang Laun <wolfgang.laun at gmail.com>

> Assuming you have
>
>    class ApplicationData{ String age; int intAge;... }
>
> you might do
>    rule one
>    when
>       ad : ApplicationData( $age: age != null && != "" && matches "\\d+" )
>    then
>       modify( ad ){ setIntAge( Integer.parseInt($age)  ) }
>    end
>   rule two
>    when
>       ad : ApplicationData( intAge < 0 )
>    then
>       ...error...
>    end
>
> Or, anoither possibilitie:
>   when
>    ad : ApplicationData( $age: age != null && != "" && matches "\\d+" )
>    eval( Integer.parseInt($age) < 0 )
>  then
>    ...error...
>  end
>
> -W
>
> On 25 March 2011 18:46, Benson Fung <benson.redhat at gmail.com> wrote:
>
>> so how can I change it to integer in the rule?
>>
>>
>>
>> 2011/3/26 Wolfgang Laun <wolfgang.laun at gmail.com>:
>> > If it's stored in a fact field of type int: yes.
>> >
>> > The way you write it: no.
>> >
>> > -W
>> >
>> >
>> > On 25 March 2011 18:37, Benson Fung <benson.redhat at gmail.com> wrote:
>> >>
>> >> If the age is String type, can I use Integer.parseInt(age) to change
>> >> to integer and then evaluate it?
>> >>
>> >> like
>> >>
>> >> when
>> >>   ad : ApplicationData(Integer.parseInt(age) < 0)
>> >> then
>> >>  ad.setReturnMsg("age should not be negative 0")
>> >> end
>> >>
>> >>
>> >>
>> >>
>> >> 2011/3/26 Wolfgang Laun <wolfgang.laun at gmail.com>:
>> >> > Sorry, I don't use guided editors.
>> >> > -W
>> >> >
>> >> > On 25 March 2011 18:17, Benson Fung <benson.redhat at gmail.com> wrote:
>> >> >>
>> >> >> Hi Wolfgang,
>> >> >>
>> >> >> I managed to author this rule(ApplicationData( age == null || age ==
>> >> >> "" )) via Technical Rules editor of BRMS.
>> >> >> However, I cannot create this rule via Business Rule Guided Editor
>> of
>> >> >> BRMS.
>> >> >>
>> >> >> Could you let me know how?
>> >> >>
>> >> >>
>> >> >> Thanks
>> >> >>
>> >> >>
>> >> >>
>> >> >> 2011/3/26 Wolfgang Laun <wolfgang.laun at gmail.com>:
>> >> >> > You can't use a method call as the left hand side operand in a
>> >> >> > constraint;
>> >> >> > thus
>> >> >> >    age.size() == 0
>> >> >> > is not correct.
>> >> >> >
>> >> >> > Do you really mean
>> >> >> >    age == "null"
>> >> >> >
>> >> >> > Probably
>> >> >> >   ApplicationData( age == null || age == "" )
>> >> >> > is the right thing to do, provided that ApplicationData.age is a
>> >> >> > String.
>> >> >> >
>> >> >> > -W
>> >> >> >
>> >> >> > On 25 March 2011 17:32, Benson Fung <benson.redhat at gmail.com>
>> wrote:
>> >> >> >>
>> >> >> >> Hi,
>> >> >> >>
>> >> >> >> I got the following rule problem.
>> >> >> >>
>> >> >> >> The rule is like :
>> >> >> >>
>> >> >> >> 1.      |       rule "Rule1"
>> >> >> >> 2.      |           dialect "mvel"
>> >> >> >> 3.      |           when
>> >> >> >> 4.      |               ad : ApplicationData( age == "null" ,
>> >> >> >> age.size()
>> >> >> >> == 0)
>> >> >> >> 5.      |           then
>> >> >> >> 6.      |               ad.setReturnMsg( "age should not be null
>> or
>> >> >> >> empty"
>> >> >> >> );
>> >> >> >> 7.      |       end
>> >> >> >>
>> >> >> >> where setReturnMsg is a method of ApplicationData Fact();
>> >> >> >>
>> >> >> >> However, I got the validation error :
>> >> >> >>
>> >> >> >> [Rule1] [ERR 101] Line 4:49 no viable alternative at input ')' in
>> >> >> >> rule
>> >> >> >> "Rule1" in pattern ApplicationData
>> >> >> >> [Rule1] [ERR 102] Line 4:51 mismatched input '==' expecting ')'
>> in
>> >> >> >> rule "Rule1" in pattern ApplicationData
>> >> >> >>
>> >> >> >> Please help what the problem is.
>> >> >> >>
>> >> >> >>
>> >> >> >> Thanks
>> >> >> >> _______________________________________________
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>> >> >> >> https://lists.jboss.org/mailman/listinfo/rules-users
>> >> >> >
>> >> >> >
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>> >> >>
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>> >> >
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>
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