Arsalan,

    Unfortunately Drools does not have a field constraint negation operator, mostly because when writing rules, it was not needed, since you can always negate the constraint itself.
    Although, I understand a agree with your use case. My suggestion is for you to open a JIRA feature request and we will include that as soon as possible in the product.
    Although, meanwhile, the only workaround I can see for your case is to translate the expression you are using directly into a java or mvel expression and write it inside an in-line eval.

    []s
    Edson

2007/9/14, Arsalan S. Zaidi <arsalan.zaidi@capgemini.com>:

Hi

 

I'll try to explain the situation that Gaurav finds himself in. We're working on this problem together and so far, we haven't been able to crack it.

 

We're using drools to handle the business rules for an application. The rules however, are not provided to us in a .drl file, rather, we get an XLS sheet from the analysts with rules in a different grammar.

 

We're using ANTLR to read and parse these rules to generate the drools rules programmatically. However, we're running into problems with NOT.

 

The input rules (in the non-drools business language) have a NOT operator which works like '!' in Java. It flips the Boolean around, so to speak. So:

 

NOT((some sub expression which evaluates to TRUE)) == FALSE

 

MVEL doesn't seem to support this. So how do we simulate it?

 

If it were only being used with NOT IN, we could manage, but its use is completely arbitrary. Changes to the input rules or to the input rules grammar have been (ha ha) ruled out.

 

Any help would be appreciated.

 

Regards,

_____________________________________________________

Arsalan Zaidi / Capgemini - India (FS SBU) / Mumbai

Technical Architect
Mobile Phone: +91 9892 8970 03 /
www.capgemini.com


Together: the Collaborative Business Experience
_____________________________________________________


From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Anstis, Michael (M.)
Sent: 13 September 2007 13:31
To: Rules Users List
Subject: RE: [rules-users] How to use not operator in drool.

 

What dialect do your rules use?

 

You could also simplify the logic using DeMorgans Theorem (which might be troublesome to accomplish programmatically)

 

I don't know whether your example is flawed as the brackets don't match, but assuming you mean something like this:-

 

(NOT (G13.1 IN ("1","2","3") OR (G250.8 = Y)))

 

You can re-write this as

 

 

(G13.1NOT IN ("1","2","3") AND G250.8 != Y)

 

With kind regards,

 

Mike

 

 


From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of JOSHI, GAURAV
Sent: 13 September 2007 08:20
To: Rules Users List
Subject: RE: [rules-users] How to use not operator in drool.

Thank's for your sugession of using "not in" instead of "not" but my problem is that "not" can also come without "in".

 

Actually I am making a generator of rule file from expression like

 ((NOT (ENDS WITH (G10.2, ",")))

 

 ((NOT (G13.1 IN ("1","2","3"))) OR (G250.8 = Y)))

 

Where G13.2, G250.8, G10.2 are variables coming from a map inserted in working memory.

 

I am accessing these variables from map.

 

My rules are as follows

 

This rule is working fine.

 

rule "Editable_G10.3"

when

 

 ((Map( this["G10.3"] !=8))||(Map( this["G10.2"] ==19)))

 

then

System.out.println("comming here----------------------------------------------------->");

End

 

This is not working

 

rule "Mandatory_G10.3"

when

 (not((Map( this["G10.3"] !=8))||(Map( this["G10.2"] ==19))))

Then

System.out.println("comming here----------------------------------------------------->");

End

 

In also tried following approaches:

1)      eval(not((Map( this["G10.3"] !=8))||(Map( this["G10.2"] ==19))))

 

2) eval(!((Map( this["G10.3"] !=8))||(Map( this["G10.2"] ==19))))

 

But in both cases it is giving same error:

org.drools.rule.InvalidRulePackage: Rule Compilation error : [Rule name=ValidationRuleExp_G10.3, agendaGroup=MAIN, salience=0, no-loop=false]

      com/telekurs/nva/mde/fe/ak/validation/Rule_ValidationRuleExp_G10_3_0.java (11:495) : Cannot use this in a static context

      com/telekurs/nva/mde/fe/ak/validation/Rule_ValidationRuleExp_G10_3_0.java (11:500) : Type mismatch: cannot convert from String to int

 

I am trying to find out some general concept so that I can change just achieve the functionality of not.

 

Thanks

Gaurav

 


From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Edson Tirelli
Sent: Wednesday, September 12, 2007 10:20 PM
To: Rules Users List
Subject: Re: [rules-users] How to use not operator in drool.

 


   Remove your "eval" and use "or" instead of "||" for the OR CE.

   Although, I feel that this is not what you want... what you want is simply:

when
    Map( this['city'] not in ( "mumbai", "delhi" ) )
then
    //...
end
 
    []s
    Edson

2007/9/12, Gaurav2007 < gaurav.a.joshi@capgemini.com>:


Hi ALL,

I am using drool4.0.1 in my application i am able to use IN,OR,AND operator
but i am facing problem in using not operator.

my requirement of not operator is just like a not gate.

the way i am using it is :

eval(not((Map( this["city"] !="mumbai"))||(Map( this["city"] =="delhi"))))


so can you please help me out to solve this problem:
should i use not operator or some thing else in drool.

Thanks,


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  Edson Tirelli
  Software Engineer - JBoss Rules Core Developer
  Office: +55 11 3529-6000
  Mobile: +55 11 9287-5646
  JBoss, a division of Red Hat @ www.jboss.com

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--
  Edson Tirelli
  Software Engineer - JBoss Rules Core Developer
  Office: +55 11 3529-6000
  Mobile: +55 11 9287-5646
  JBoss, a division of Red Hat @ www.jboss.com