What is the relationship (extends/implements) between the classes/interfaces in your model - ContextFoodItem, FoodItem, ContextDiner, etc.. ? Could you also please specify the version of Drools you are using? Thanks! Davide On 07/07/2014 03:04 PM, Borris wrote: > I am getting an unexpected cast exception. The backtrace looks like > > Exception in thread "main" java.lang.ClassCastException: > com.tastiereasier.rulez.ContextFoodItem cannot be cast to > com.tastiereasier.domain.FoodItem > at > ConditionEvaluatorb792d1e4169f4ac98945e49e1412d793.evaluate(Unknown Source) > at > org.drools.core.rule.constraint.MvelConstraint.evaluate(MvelConstraint.java:216) > at > org.drools.core.rule.constraint.MvelConstraint.isAllowedCachedLeft(MvelConstraint.java:185) > at > org.drools.core.common.SingleNonIndexSkipBetaConstraints.isAllowedCachedLeft(SingleNonIndexSkipBetaConstraints.java:141) > at > org.drools.core.phreak.PhreakJoinNode.doLeftInserts(PhreakJoinNode.java:98) > at org.drools.core.phreak.PhreakJoinNode.doNode(PhreakJoinNode.java:60) > at > org.drools.core.phreak.RuleNetworkEvaluator.switchOnDoBetaNode(RuleNetworkEvaluator.java:547) > at > org.drools.core.phreak.RuleNetworkEvaluator.evalBetaNode(RuleNetworkEvaluator.java:533) > at > org.drools.core.phreak.RuleNetworkEvaluator.innerEval(RuleNetworkEvaluator.java:334) > at > org.drools.core.phreak.RuleNetworkEvaluator.evalStackEntry(RuleNetworkEvaluator.java:224) > at > org.drools.core.phreak.RuleNetworkEvaluator.outerEval(RuleNetworkEvaluator.java:166) > at > org.drools.core.phreak.RuleNetworkEvaluator.evaluateNetwork(RuleNetworkEvaluator.java:116) > at > org.drools.core.phreak.RuleExecutor.reEvaluateNetwork(RuleExecutor.java:193) > at > org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:68) > at > org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:928) > at > org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1193) > at > org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1202) > at > org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1175) > at com.tastiereasier.rulez.Rulez.insertAndFire(Rulez.java:168) > at com.tastiereasier.rulez.Rulez.addDinerToContext(Rulez.java:310) > at com.tastiereasier.rulez.Rulez.<init>(Rulez.java:101) > at com.tastiereasier.rulez.Rulez.main(Rulez.java:44) > > The rules that are triggering this are: > > rule contextDinerDislike > enabled true > when > ContextDiner( $diner; ) > DatumPreference > ( > datumPreferenceType == DatumPreference.Type.PREFERENCE, > belief.factor < 0.0, > $datum: datum > ) > from $diner.getDatumPreferences() > then > insert( new ContextFoodItem( (FoodItem) $datum, true ) ); > end > > rule spotNewContextDinerLike > enabled true > when > ContextDiner( $diner; ) > DatumPreference > ( > datumPreferenceType == DatumPreference.Type.PREFERENCE, > belief.factor > 0.0, > $datum: datum > ) > from $diner.getDatumPreferences() > then > insert( new ContextFoodItem( (FoodItem) $datum, false ) ); > end > > If I disable either rule, then the other proceeds fine and no cast > exception happens. > > I can't see why the cast should ever be asked for - it doesn't make sense. > > If I changed the boolean parameter in the new in the insert - so both > are either true or both > are either false, there are no cast exceptions (there must be a clue here). > > If I put a debug after the insertion, the backtrace actually happens > after return from the > insert() method - implying it's something on the agenda? > > I tried using the Audit stuff to see if it gave any clues - but I've > never used that before > and simply got a heap exhaustion from Eclipse after 1/2 hour trying to > ingest something like 200 > meg of trace data - I've got a lot of data being initialised into the > workspace before these rules > get a chance to do anything. > > It's feeling remarkably like a bug to me, but I don't know how to > interpret the backtrace usefully, > so it's possible I've got something messed up elsewhere - although I've > disabled massive amounts > of rules that I can. > > I grabbed a snapshot last night and it didn't change anything. (I was on > a snapshot from early June to fix being able to have Drools editor > reference my external jars.) > > Does this look like a bug or user error? It's going to take some effort > to try and extract a test case > so I really don't want to spend the effort on that unless it looks the > only way. > > Sage observations most appreciated. > > Borris > > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

On Monday 07/07/2014 23:09, Borris wrote: > Hi, > > Thanks for the response. > > Version is now 6.1.0.201407061813 (snapshot from last night). Previous > version was 6.1.0.201406070605 (snapshot from about a month ago). I was > on a snapshot because I wanted the fix for this: > https://github.com/droolsjbpm/droolsjbpm-tools/commit/6bc54748e Slight "my bad" - I'd forgoten to do a new runtime and use that. Fixed. Still get the same issue, but some of the line numbers are slightly different, in case that's relevant. Exception in thread "main" java.lang.ClassCastException: com.tastiereasier.rulez.ContextFoodItem cannot be cast to com.tastiereasier.domain.FoodItem at ConditionEvaluator3754d879fb5b46a3b2cfbe61326ba9f5.evaluate(Unknown Source) at org.drools.core.rule.constraint.MvelConstraint.evaluate(MvelConstraint.java:216) at org.drools.core.rule.constraint.MvelConstraint.isAllowedCachedLeft(MvelConstraint.java:185) at org.drools.core.common.SingleNonIndexSkipBetaConstraints.isAllowedCachedLeft(SingleNonIndexSkipBetaConstraints.java:141) at org.drools.core.phreak.PhreakJoinNode.doLeftInserts(PhreakJoinNode.java:98) at org.drools.core.phreak.PhreakJoinNode.doNode(PhreakJoinNode.java:60) at org.drools.core.phreak.RuleNetworkEvaluator.switchOnDoBetaNode(RuleNetworkEvaluator.java:547) at org.drools.core.phreak.RuleNetworkEvaluator.evalBetaNode(RuleNetworkEvaluator.java:533) at org.drools.core.phreak.RuleNetworkEvaluator.innerEval(RuleNetworkEvaluator.java:334) at org.drools.core.phreak.RuleNetworkEvaluator.evalStackEntry(RuleNetworkEvaluator.java:224) at org.drools.core.phreak.RuleNetworkEvaluator.outerEval(RuleNetworkEvaluator.java:166) at org.drools.core.phreak.RuleNetworkEvaluator.evaluateNetwork(RuleNetworkEvaluator.java:116) at org.drools.core.phreak.RuleExecutor.reEvaluateNetwork(RuleExecutor.java:216) at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:91) at org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:964) at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1234) at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1239) at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1212) at com.tastiereasier.rulez.Rulez.insertAndFire(Rulez.java:168) at com.tastiereasier.rulez.Rulez.addDinerToContext(Rulez.java:310) at com.tastiereasier.rulez.Rulez.<init>(Rulez.java:101) at com.tastiereasier.rulez.Rulez.main(Rulez.java:44) _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

I'll try to reproduce the exception with the rule and the data model. Meanwhile, could you share a self-contained unit test that reproduces the problem? That would speed up the fix process Thanks! Davide

On Monday 07/07/2014 23:26, Davide Sottara wrote: > I'll try to reproduce the exception with the rule and the data model. > Meanwhile, could you share a self-contained unit test that reproduces > the problem? > That would speed up the fix process > Thanks! > Davide Hmm. Worked out what is happening. The exception is triggered by these: rule handleComplexFoodItemClash enabled false when $first: ContextFoodItem( $item, true; ) $second: ContextFoodItem( this != $item, avoid == false ) isExampleOf( $second, $first; ) then retract($second); end query isExampleOf (FoodItem $subject, FoodItem $category) ( eval($subject == $category) ) or ( BroaderNarrower($broader, $subject;) and ?isExampleOf($broader, $category;) ) end This is the last thing I was playing with, so maybe not surprising there's an error (the exception arises because of the isExampleOf query and is a simple bug for me to fix). BUT BUT BUT I have "enabled false" as a rule attribute. Am I missing something - I expected this to mean that the when part is never evaluated, but it looks more like the when part is evaluated but consequences are not added to the agenda. The documentation is sufficiently terse that both viewpoints could be argued :( Borris _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

On Wednesday 09/07/2014 14:41, Davide Sottara wrote: > Sorry for not being able to get back to you again earlier. > Yes, the rule / query you are showing makes sense - I would have asked > you for something similar :) It is definitely a bug in the resolution of > the class that defines an attribute, we could really use the reproducer > to fix it quickly. > > I'll check the "enabled" attribute's behavior in 6.x > Thanks > Davide I'll tidy up the the test case I've generated and email it to you. Just to be clear, the cast exception was caused by a mistake on my part in the when part of a rule, but in a rule with an "enabled false" attribute. I had done the standard thing of gradually disabling bits until the error went away, but had not allowed for the exception being triggered with enabled false, so had assumed (not unreasonably I argue :) ) that the initially supplied rules must be the cause of the problem. At least, that's my conclusion - but the test case will let you decide independently. Borris _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users