Re: [rules-users] Avoiding writing redundant rules

A couple of things come to mind with regards to your "example solution": 1. Will there only ever be one Person in working memory that can match and trigger your first rule? If not, setting a single boolean will only indicate that the first rule has fired at least once, not for each Person, or one Person, or two... or whatever your requirement is. 2. I usually accomplish this with a place holder fact or a fact created as an extension of a, for example your Person, class. This also acts as a place holder. I agree, I don't like having duplicated code that is just negated because as we know, negating a "simple rule" can turn out to be not such a simple thing to do. Earnie! ________________________________ From: skasab2s <skasab2s(a)smail.inf.fh-brs.de&gt; To: rules-users(a)lists.jboss.org Sent: Mon, July 19, 2010 12:57:39 PM Subject: [rules-users] Avoiding writing redundant rules Hello, in our company we use DRL-files and we have the problem with the fact, that rules have no 'else'-part. We've read in this forum, that we can simulate the else-part of a rule by declaring a new rule which has the constraints of the first rule, but negated. We regard this as some kind of redundancy in our code , besides our rule-files become twice as large and drools have to evaluate the (almost) same constraints twice. We wanted to ask you if it makes sense to declare additional variables in order to mark if a rule has fired. Something like this: <code> declare FirstRuleHasFired value: boolean end ... //Insert an object from type FirstRuleHasFired ... rule "FirstRule" salience 100 when Person (name) then //do some job firstRuleHasFired.setValue(true) ; end rule "SecondRule" salience 90 when not(FirstRuleHasFired(value == true)) then //do some other job ) .. </code> Or do you know some other useful tricks to avoid the redundancy I have written about? Thanks a lot for every idea and/or advice! Regards, skasab2s -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Avoiding-writing-redu... Sent from the Drools - User mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users