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

[Greg Barton]

See the current discussion of accumulate functions.  That should satisfy your need.

GreG

On Jan 29, 2011, at 10:18, OlliSee <o.roess at seeburger.de> wrote:

> 
> 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)
> 
> -- 
> View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Writing-a-pattern-in-which-each-event-constraint-depends-on-the-previous-event-tp2370165p2370165.html
> Sent from the Drools - User mailing list archive at Nabble.com.
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users