[rules-users] Hard constraint on selecting a skill

Hello! I'm still not getting good with drools rules, i'm trying several examples and basic ones. Some i did without any problem and understood plenty well, but when I try to make an approach to what i'm aiming, I'm not able to. Right now I'm trying to compose this: When there's an workorder with skill and there's and engineer with the skill and capable of doing that workorder then the engineer should do it So i tried something like this: rule "assignSkillWOToSkilledEngineer" when $wo : WorkOrder( $requiredSkill : requiredSkill ) $engineer : Engineer(skill == $requiredSkill) then insertLogical(new IntConstraintOccurrence("assignSkillWOToSkilledEngineer", ConstraintType.NEGATIVE_HARD, 1, $engineer)); end i get no exceptions, but the sort is not working properly