I'm trying out stream mode and having some trouble. I'm setting
drools.eventProcessingMode to stream and using an entry point for inserting
some objects. Sometimes (but not all of the time) the rule that matches on
objects from the entry point (currently the only rule in the ruleset) will get
a null reference for the object retrieved from the entry point. Here's the drl:
declare Incoming
@role( event )
@expires( 15s )
end
rule "entry"
no-loop true
when
i: Incoming() from entry-point "Incoming";
e: Existing(matcher == i.matcher);
then
if(i == null) {
System.err.println("NULL MATCHED WITH " + e.getMatcher());
} else {
if(e.incorporate(i)) {
update(e);
System.out.println(e);
}
}
end
Sometimes (not not all of the time) I get these in stderr:
NULL MATCHED WITH Matcher1
NULL MATCHED WITH Matcher12
NULL MATCHED WITH Matcher3
NULL MATCHED WITH Matcher9
The Incoming objects are added at a high rate (sometimes thousands per second)
so my guess was that they weren't being processed fast enough and were being
expired before the rule action could fire. I changed their @expires value to
"1d" and then got one of the two exceptions below when I ran the application.
Some more details: I use WorkingMemoryEntryPoint.insert() to add the Incoming
objects. The StatefulKnowledgeSession runs in a separate thread, blocking on
fireUntilHalt().
Here are the exceptions I often incur on calling
WorkingMemoryEntryPoint.insert() with the long expiration. Rule execution
halts after the exception:
Exception in thread "Thread-5" java.lang.NullPointerException
at org.drools.util.RightTupleList.matches(RightTupleList.java:167)
at
org.drools.util.RightTupleIndexHashTable.get(RightTupleIndexHashTable.java:292)
at
org.drools.util.RightTupleIndexHashTable.getFirst(RightTupleIndexHashTable.java:87)
at org.drools.reteoo.JoinNode.assertLeftTuple(JoinNode.java:112)
at
org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:117)
at
org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:28)
at org.drools.reteoo.JoinNode.assertObject(JoinNode.java:175)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:42)
at
org.drools.reteoo.PropagationQueuingNode$AssertAction.execute(PropagationQueuingNode.java:326)
at
org.drools.reteoo.PropagationQueuingNode.propagateActions(PropagationQueuingNode.java:221)
at
org.drools.reteoo.PropagationQueuingNode$PropagateAction.execute(PropagationQueuingNode.java:394)
at
org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1464)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:156)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:120)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:78)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:26)
at org.gregcode.stuff.analysis.Analyzer.add(Analyzer.java:108)
at org.gregcode.stuff.Simulator$1.run(Simulator.java:69)
at java.lang.Thread.run(Thread.java:619)
Exception in thread "Thread-3" java.lang.NullPointerException
at org.drools.util.LeftTupleList.add(LeftTupleList.java:48)
at
org.drools.reteoo.RuleTerminalNode.assertLeftTuple(RuleTerminalNode.java:245)
at
org.drools.reteoo.RuleTerminalNode.assertLeftTuple(RuleTerminalNode.java:165)
at
org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:117)
at
org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:28)
at org.drools.reteoo.JoinNode.assertLeftTuple(JoinNode.java:116)
at
org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:117)
at
org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:28)
at org.drools.reteoo.JoinNode.assertObject(JoinNode.java:175)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:42)
at
org.drools.reteoo.PropagationQueuingNode$AssertAction.execute(PropagationQueuingNode.java:326)
at
org.drools.reteoo.PropagationQueuingNode.propagateActions(PropagationQueuingNode.java:221)
at
org.drools.reteoo.PropagationQueuingNode$PropagateAction.execute(PropagationQueuingNode.java:394)
at
org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1464)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:156)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:120)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:78)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:26)
at org.gregcode.stuff.analysis.Analyzer.add(Analyzer.java:108)
at org.gregcode.stuff.Simulator$1.run(Simulator.java:69)
at java.lang.Thread.run(Thread.java:619)
Thanks!
GreG
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