RE: [rules-users] Can only reason over sub-objects if you use the FromConditional Element

IMO, you have not informed the engine\RETE network that details have changed in your first example. This would probably be a better example:- rule "30 is the new 20" when person : Person( $d : details.age == 30 ) then person.getDetails().setAge(20); System.out.println( "Now 20 : " + person ); update( person ); update( $d ); end The From works because it gets external data rather than using that already in the engine\RETE network. IMO, I think the rules are working correctly; it's just a misunderstanding of how the engine\RETE network function. I hope this helps. Thanks, Mike -----Original Message----- From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Aaron Dixon Sent: 14 March 2008 20:51 To: Rules Users List Subject: [rules-users] Can only reason over sub-objects if you use the FromConditional Element It appears that you MUST use the From Condition Element to reason over sub-objects. I have a Person class. Person::getDetails() returns a Details instance, which has the name and age of the person. (This is a contrived example to demonstrate the issue.) My rules are: rule "30 is the new 20" when person : Person( details.age == 30 ) then person.getDetails().setAge(20); System.out.println( "Now 20 : " + person ); update( person ); end rule "Older than 20 - Good" salience -100 when person : Person( ) Details( age > 20 ) from person.details then System.out.println( "Older than 20 (good) : " + person ); end rule "Older than 20 - Bad" salience -100 when person : Person( details.age > 20 ) then System.out.println( "Older than 20 (bad) : " + person ); end I assert Abe, Bob, Cat, Don, and Eve with ages of 10, 20, 30, 40, and 50, respectively. The output is as follows. Now 20 : Person(Details(Cat,20)) Older than 20 (good) : Person(Details(Eve,50)) Older than 20 (bad) : Person(Details(Eve,50)) Older than 20 (good) : Person(Details(Don,40)) Older than 20 (bad) : Person(Details(Don,40)) Older than 20 (bad) : Person(Details(Cat,20)) You can see that the "Bad" rule is more concise but it does not use the From Conditional Element and therefore it doesn't work properly (Cat is determined to be older than 20 when she is not.) Why does Drools allow the "Bad" rule to be written and compiled when it does not behave properly? Thanks, Aaron _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users