Re: [rules-users] Chart notation, update, and infinite loops

From: Dan Seaver <dan.seaver(a)ge.com&gt; Subject: Re: [rules-users] Chart notation, update, and infinite loops To: rules-users(a)lists.jboss.org Date: Tuesday, November 4, 2008, 2:08 PM Thanks Edson, I'm aware of "accumulate" and see how it can be used to solve the specific issue. I'm looking for a more generic solution for updating objects. The only reason amountFact is part of the "when" clause is for a reference to the object that can be used by the "then" clause. It's not really part of the rule criteria. If I could get a reference to it directly in the "then" clause, the update statement would not put the rule back on the agenda - which would be perfect. Any ideas? Dan Edson Tirelli-3 wrote: > > There are several ways of doing that, and some where even mentioned by > the other users. One easy way is to simply use "accumulate": > > rule "update amount" > no-loop > when > $f : Fact( name == "amount" ) > Number( $total : doubleValue ) from accumulate( > Charge( $amt : amount ), > sum( $amt ) ) > then > modify( $f ) { setAmount( $total ) } > end > > []s > Edson > > 2008/11/4 Dan Seaver <dan.seaver(a)ge.com&gt; > >> >> I'm trying to find a good technique for updating specific facts in >> working >> memory. What I'm currently doing is something like this: >> >> Rule "Update Amount" >> when >> amountFact : Fact(name == "Amount") >> charge : Charge() >> then >> Double amount = amountFact.getAmount(); >> Double chargeAmount = charge.getAmount(); >> amountFact.setAmount(amount + chargeAmount); >> update(amountFact); >> end >> >> The update statement causes an infinite loop. >> I tried using no-loop, which works if there is 1 charge, but not if there >> are more than one. >> >> Any help with solutions or strategies would be much appreciated. >> -- >> View this message in context: >> http://www.nabble.com/Chart-notation%2C-update%2C-and-infinite-loops-tp20... >> 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 >> > > > > -- > Edson Tirelli > JBoss Drools Core Development > JBoss, a division of Red Hat @ www.jboss.com > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > -- View this message in context: http://www.nabble.com/Chart-notation%2C-update%2C-and-infinite-loops-tp20... 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