Requirement: 1) Rule When Person.address.address1 is changed THEN 2) Ideally we should have 2 objects, 1 for the old person instance, the other for the new person instance so contextually the LHS equals to oldPerson.address.address1 != newPerson.address.address1. A properties change listener might not be the best solution as it might span multiple calls and the property change could be done on the web layer which is out of the JBoss Drools knowledge session. Ivan -- View this message in context: http://drools.46999.n3.nabble.com/How-to-write-Drools-rule-basing-on-a-ch... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

Thanks, when I am saying person address is changed, our app only concerns about its initial value and its final value, any change in the middle, we don't care. Examples: person.address.address1 starts with 'my addr1' later a couple of changes were made, say its final value is 'my addr1', we treat it as no change and no middle rules should be fired. Even for the 2 objects approach, how I can write the rules to get the old and new object matched correctly? They are both Person instances without any identity to tell which one is the old which one is the new one, unless I enable some kinds of map/or list in the rule and one structure to host only new objects and the other one hosts only the old values? -- View this message in context: http://drools.46999.n3.nabble.com/How-to-write-Drools-rule-basing-on-a-ch... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users