4:04 p.m.
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