Here is the code snipet.

rule "Validation"

when

                $claim: Claim($cos: claimIdentificationInfo.categoryOfService !=null);

                $claimId: ClaimIdentification($cos not in ("01","03","04"), $cos.length >0);

then

                log.info("Executing Rule: Validation .............");

end

Above code works if

- $cos in ("01","03","04")

-$cos.length

But when I put not in front of in (“not in”), it throws exception like this…

Unable to build constraint as  '$cos' is invalid : [Rule name='Validation']