Re: [rules-users] Identity, equality, hashing and indexing

-----Original Message----- From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users- bounces(a)lists.jboss.org] On Behalf Of Bruno Freudensprung Sent: 08 December 2010 14:00 To: Rules Users List Subject: [rules-users] Identity, equality, hashing and indexing Hi, I have some existential questions about Drools Expert's magic :-). When reading the documentation it is clear that, by default, facts are stored in an IdentityHashMap. If I understand things correctly it means that the objects I put in the working memory don't have to implement the hashCode() and equals() method. They should implement them only if I tell Drools to use the "equality mode". So here is my first question: in equality mode, if a fact field is used by the hashCode method, and if that field is modified by a rule action, should I expect a weird behavior since facts are stored in a HashMap? When digging into rules-users' archives I also found posts of Mark Proctor, talking about field indexing and alpha node hashing, that lead to my second question: should I expect a weird behavior if 2 fields are related to each other? For instance (not a good example but it gives an idea): a Person type has a getFirstName() method, a getLastName() method and a getName() method that return the concatenation of getFirstName() and getLastName(). Is it problematic if one rule has a "Person(name == "John Doe")" fact in its LHS and if another rule modifies the "firstName" of that Person fact (John -> Jane)? Does it depend on the equality vs. identity mode (I don't think so... unless the field itself is a also a fact)? Many thanks in advance for your answers, Best regards, Bruno. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users