Re: [rules-users] Accessing maps (hashmaps) keys and values in rules
Hi,
I can't seem to make this syntax work in Drools 4.0.2. Pls. see my sample
code below.
________________________________________
class MyClass {
String id;
String name;
MyClass(String id, String name){
this.id = id;
this.name = name;
}
:
getter, setter methods
:
}
MyClass obj = new MyClass("1"", "name");
TreeMap<String, MyClass> mapOfObj = new TreeMap<String, MyClass>();
mapOfObj.put("keyOfObj", obj);
________________________________________
DRL file
-------
global java.util.TreeMap mapOfObj;
rule chkobj
when
obj : MyClass(mapOfObj["keyOfObj"].id == "1");
eval(obj.getName() == "name");
________________________________________
I'm getting this error: org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at
org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:76)
Is my syntax correct and has someone used this in 4.0.2 or should I move on
to Drools 4.0.3? Thanks in advance.
Regards,
shaz
Edson Tirelli-3 wrote:
Denis,
If you are using latest build from trunk (I'm not sure it already works
in MR3), you can use a simplified MVEL syntax:
when
Person( address["business"].phone == "99999999" )
then
...
end
Although, the above will be converted into an inline-eval. Not as bad
as
a top level eval, but still more costly then using regular fields.
[]s
Edson
2007/7/19, Ryan, Dennis (Dennis) <dennisryan(a)avaya.com>:
>
> We are using Maps (HashMaps) in our rules and the only way we have found
> to access keys and values in the Map in the "when" clauses is thru use on
> eval() which I know is a big no-no by rules purists. Is there a better
> way,
> maybe some shorthand I'm not familiar with to deal with Maps in the when
> clause?
>
>
>
> Thanks,
>
> Dennis
>
> _______________________________________________
> 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 3529-6000
Mobile: +55 11 9287-5646
JBoss, a division of Red Hat @ www.jboss.com
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