[rules-users] newbie: update and shallowCache

Hi all, I am evaluating Drools and am stuck with a simple rule that selects elements which do not correspond to the condition... Since I am updating objects in the RHD, I guess it has to do with my wrong understanding (and the cache...?) I am trying to allocate lessons to periods (hour). My object model can be summarize is as follows : Lesson boolean : allocated // true if the lesson has been allocated to an hour int : session // a session is a bunch of lessons Subject : subject // an allocated lesson is assigned a subject Subject Set<Day> : allocatedDays // days in which this subject is taught - checked before allocation, as a subject can only be taught once a day Hour boolean : allocated // true is this hour has been allocated with a lesson Day : day // the day this hour belongs to - required to check with subject.allocatedDays I put in the workingMemory a bunch of Lesson objects, which have been set with Subject and Session id. I also put a bunch of Hour object, set with a Day. My rule is as follows: rule "allocate" when $lesson : Lesson(allocated == false, session.type == Session.DISTINCT, $allocatedDays : subject.allocatedDays) $availableHour : Hour(allocated == false, day not memberOf $allocatedDays) then $lesson.setHour($availableHour ) ; $lesson.setAllocated(true) ; update($lesson); $availableHour.setSubject($lesson.getSubject()) ; $availableHour.setAllocated(true ); update($availableHour); end When I set a debug on the first line of the THEN section, I can see that sometimes $availableHour.allocated == true ... sometimes $lesson.allocated == true (although it's an implicit And statement ...) Therefore, I can see that the update() works, but it seems that the rule does not use the updated object (due to shallow copy ??) Any help more than welcome Regis