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 :

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

Set<Day> : allocatedDays // days in which this subject is taught - checked before allocation, as a subject can only be taught once a day

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