[rules-users] Best practice for "drool-ing" a complex object

Hi, I have perhaps a simple question. Here is my complex Object: public class Object1 { private String id; private Set<Object2> obj2s; } public class Object2 { private String idof2; private Object3 obj3; private Object4 obj3; } The business logic depends on the Object1 and all of the Object2 in the list. My question is what is the best way to pass this to drools and have the rules be applied. I read somewhere that the best is to have "flat" objects, with no lists, then pass those objects into the engine. However with 4.0there is a way to go through the lists, but it is still not suggested. Is that correct ? Any suggestions are welcomed. Thanks. Krk