Re: [rules-users] newbie: update and shallowCache

Hi Edson, Thanks for your help. I restructured my biz objects to avoid nested structures, which makes it work now (I have new objects to hold allocatedHour per subject). However, I have the feeling that this constraint has a certain impact on o-o design (more flat objects vs composite object). The documentation says that nested values should be considered immutable, unless using the modify block (as you suggested) and retract/re-assert the objects in the workingMemory ; it also has a much greater performance cost. Am I getting it right when saying that the object design should really be like 'many flat-type objects avoiding composite approach' to have Drools perform well or is it more sensible to have a proper o-o design and tweak Drools (using modify block, disabling cache, etc.) Thanks in advance for sharing your experience Regis * when * $lesson : Lesson(allocated == *false* , session.type == Session.DISTINCT) $subjectAllocation : SubjectAllocation( subject == $lesson.subject, $allocatedDays : 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) ; $subjectAllocation.addAllocation($availableHour ) ; *update*($subjectAllocation) ; ------------------------------ *From:* rules-users-bounces(a)lists.jboss.org [mailto: rules-users-bounces(a)lists.jboss.org] *On Behalf Of *Edson Tirelli *Sent:* Monday, April 14, 2008 4:55 PM *To:* Rules Users List *Subject:* Re: [rules-users] newbie: update and shallowCache Regis, You are probably having problems with mutable predicates, when using " subject.allocatedDays". As a first step to understand your problem, I strongly encourage you to make constraints flat, i.e., avoid using nested accessors. After you get used to what can and what can't be done, you can go back to use nested accessors. Also, I suggest you use modify() block instead of update(): * rule *"allocate" *when* $lesson : Lesson(allocated == *false*, session.type == Session.DISTINCT ) $subject : Subject( $allocatedDays : allocatedDays ) from $lesson.subject $availableHour : Hour(allocated == *false*, day *not* *memberOf*$allocatedDays) *then* modify( $lesson) { setHour($availableHour ), setAllocated(*true*) } modify( $availableHour ) setSubject($lesson.getSubject()), setAllocated(*true* ) } ** *end* Hope it helps. []s Edson 2008/4/14 Piccand, Regis <rpiccand(a)verisign.com&gt;: > 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 > > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > -- Edson Tirelli JBoss Drools Core Development Office: +55 11 3529-6000 Mobile: +55 11 9287-5646 JBoss, a division of Red Hat @ www.jboss.com _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users