[rules-users] Writing a pattern in which each constraint for an event depends on the previous event

[OlliSee]

Hello everyone.

Lets say we have StockTicks...
Is it possible to detect a monotonically decreasing StockTick stream over a
window?

If I knew the number of events I want to check on, I'd do it this way

$a : StockTick() over window:time(20s)
$b : StockTick(this after $a, price < $a.price) over window:time(20s)
...

But I don't know for how long the StockTick prices continue to decrease..
I imagine doing something like that

$list : List(size > 0) from collect(StockTick() over window:time(20s))
forall($a : StockTick() from $list
	$b : StockTick(this after $a, price < $a.price from $list
)

That results in a nice exception.
Any idea how to do this work? And more efficiently than my approach?

Thanks
Oliver




Exception in thread "Thread-1" java.lang.ClassCastException:
org.drools.common.DefaultFactHandle cannot be cast to
org.drools.common.EventFactHandle
	at
org.drools.base.evaluators.AfterEvaluatorDefinition$AfterEvaluator.evaluateCachedLeft(AfterEvaluatorDefinition.java:336)
	at
org.drools.rule.VariableRestriction.isAllowedCachedLeft(VariableRestriction.java:110)
	at
org.drools.rule.VariableConstraint.isAllowedCachedLeft(VariableConstraint.java:115)
	at
org.drools.common.DoubleBetaConstraints.isAllowedCachedLeft(DoubleBetaConstraints.java:166)
	at
org.drools.reteoo.FromNode.checkConstraintsAndPropagate(FromNode.java:274)
	at org.drools.reteoo.FromNode.assertLeftTuple(FromNode.java:138)
	at
org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateAssertLeftTuple(CompositeLeftTupleSinkAdapter.java:220)
	at
org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateAssertLeftTuple(CompositeLeftTupleSinkAdapter.java:81)
	at
org.drools.reteoo.FromNode.checkConstraintsAndPropagate(FromNode.java:279)
	at org.drools.reteoo.FromNode.assertLeftTuple(FromNode.java:138)
	at
org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateAssertLeftTuple(CompositeLeftTupleSinkAdapter.java:220)
	at
org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateAssertLeftTuple(CompositeLeftTupleSinkAdapter.java:81)
	at
org.drools.reteoo.AccumulateNode.evaluateResultConstraints(AccumulateNode.java:662)
	at org.drools.reteoo.AccumulateNode.assertObject(AccumulateNode.java:270)
	at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(CompositeObjectSinkAdapter.java:450)
	at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:378)
	at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:190)
	at org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:145)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1187)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1089)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:893)
	at
org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:238)


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