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(a)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(a)lists.jboss.org [mailto:
rules-users-bounces(a)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(a)lists.jboss.org [mailto:
rules-users-bounces(a)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(a)lists.jboss.org [mailto:
rules-users-bounces(a)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(a)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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