Re: [rules-users] NPE from reteoo.AccumulateNode

Looks like a bug in Drools to me. It has the classic hallmark of a race condition: the NPE does not happen with every run (on my system), perhaps only with 85%. Moreover, with 5.4.0 I get a similar NPE and also: Exception in thread "main" java.util.NoSuchElementException at java.util.LinkedList.remove(LinkedList.java:788) at java.util.LinkedList.removeFirst(LinkedList.java:134) at org.drools.common.PropagationContextImpl.evaluateActionQueue(PropagationContextImpl.java:344) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:342) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:298) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:123) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:53) at overrun.Main.main(Main.java:64) 5.3.0 is the last version without this bug. -W On 14/05/2013, jpbarto <Jason.P.Barto(a)gmail.com&gt; wrote: > First the specifics: JDK 1.6, Mac OSX, using Drools 5.5 Final > > The full source code and rules are pasted below but here's the gist, I have > a stateful knowledge session to which I am inserting events and running an > accumulate on the input events. I have a for loop generating the events > and > inserting them as rapidly as possible. In the rules I use an accumulator > to > calculate the average of the values contained within the events. The > behavior I'm observing is that if I insert ~120 events without any waiting > I > receive an NPE. If I Thread.sleep for even just 1ms the test goes off > without a hitch. Have I uncovered a bug which should be logged in JIRA? I > would check through JIRA to see if something similar has been logged but > I'm > so unfamiliar with the codebase, not to mention it could all just be user > error. > > The NPE is as follows: > Exception in thread "main" java.lang.NullPointerException > at > org.drools.reteoo.AccumulateNode.getFirstMatch(AccumulateNode.java:1050) > at > org.drools.reteoo.AccumulateNode.modifyLeftTuple(AccumulateNode.java:345) > at > org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateModifyChildLeftTuple(SingleLeftTupleSinkAdapter.java:259) > at > org.drools.reteoo.AccumulateNode.evaluateResultConstraints(AccumulateNode.java:676) > at > org.drools.reteoo.ReteooWorkingMemory$EvaluateResultConstraints.execute(ReteooWorkingMemory.java:590) > at > org.drools.common.PropagationContextImpl.evaluateActionQueue(PropagationContextImpl.java:350) > at > org.drools.rule.SlidingLengthWindow.assertFact(SlidingLengthWindow.java:119) > at org.drools.rule.BehaviorManager.assertFact(BehaviorManager.java:94) > at org.drools.reteoo.WindowNode.assertObject(WindowNode.java:167) > at > org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(CompositeObjectSinkAdapter.java:497) > at > org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:382) > at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:235) > at org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:240) > at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:350) > at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:311) > at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:127) > at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:55) > at drools5fusioneval.Average.main(Average.java:66) > > ### Average.java ### > package drools5fusioneval; > > import java.io.IOException; > import java.util.Random; > import org.drools.KnowledgeBase; > import org.drools.KnowledgeBaseConfiguration; > import org.drools.KnowledgeBaseFactory; > import org.drools.builder.KnowledgeBuilder; > import org.drools.builder.KnowledgeBuilderFactory; > import org.drools.builder.ResourceType; > import org.drools.conf.EventProcessingOption; > import org.drools.io.ResourceFactory; > import org.drools.runtime.StatefulKnowledgeSession; > import org.drools.runtime.rule.WorkingMemoryEntryPoint; > > class AvgDFEChannel implements org.drools.runtime.Channel { > @Override > public void send(Object o) { > System.err.println ("Recieved channel message: "+ o); > } > } > > public class Average { > public static void main(String[] args) throws InterruptedException, > IOException { > KnowledgeBaseConfiguration kbconfig = > KnowledgeBaseFactory.newKnowledgeBaseConfiguration(); > kbconfig.setOption(EventProcessingOption.STREAM); > > KnowledgeBase kbase = > KnowledgeBaseFactory.newKnowledgeBase(kbconfig); > > KnowledgeBuilder kbuilder = > KnowledgeBuilderFactory.newKnowledgeBuilder(); > > kbuilder.add(ResourceFactory.newClassPathResource("drools5fusioneval/average.drl"), > ResourceType.DRL); > if (kbuilder.hasErrors()) { > System.err.println(kbuilder.getErrors().toString()); > } > kbase.addKnowledgePackages(kbuilder.getKnowledgePackages()); > > final StatefulKnowledgeSession session = > kbase.newStatefulKnowledgeSession(); > session.registerChannel("heartbeat", new AvgDFEChannel ()); > WorkingMemoryEntryPoint ep01 = > session.getWorkingMemoryEntryPoint("ep01"); > > new Thread() { > public void run() { > session.fireUntilHalt(); > } > }.start(); > > Thread.sleep (5000); // give the engine time to get setup > > Server hiwaesdk = new Server ("hiwaesdk"); > session.insert(hiwaesdk); > long LIMIT = 120; > Random rnd = new Random (System.nanoTime()); > > for (long i = LIMIT; i > 0; i--) { > int j = rnd.nextInt (212); > ep01.insert (new IntEvent (j)); > //Thread.sleep (0x1); > } > > System.out.println (hiwaesdk); > } > } > > > ### average.drl ### > package drools5fusioneval > > declare IntEvent > @role ( event ) > @expires(15s) > end > > declare Statistics > opsec : long > total : long > end > global Statistics stats; > > rule "Init engine" > salience 100 > when > then > stats = new Statistics (); > stats.setTotal (0); > stats.setOpsec (0); > drools.getWorkingMemory ().setGlobal ("stats", stats); > System.out.println ("Engine initialized"); > end > > rule "number rule" > when > $e : IntEvent () from entry-point ep01 > $s : Server (hostname == "hiwaesdk") > then > $s.currentTemp = $e.data; > stats.setOpsec (stats.getOpsec () + 1); > stats.setTotal (stats.getTotal () + 1); > end > > rule "average temp" > when > Number ($avg : intValue) from accumulate ( > IntEvent ($temp : data) over window:length(10) from entry-point > ep01, average ($temp) > ) > $s : Server (hostname == "hiwaesdk") > then > $s.avgTemp = $avg; > end > > rule "Heartbeat" > timer ( int: 5s 5s) > when > then > channels["heartbeat"].send ("Heartbeat: "+ stats.getOpsec () / 5 +", "+ > stats.getTotal ()); > stats.setOpsec (0); > end > > > > -- > View this message in context: > http://drools.46999.n3.nabble.com/NPE-from-reteoo-AccumulateNode-tp402381... > Sent from the Drools: User forum mailing list archive at Nabble.com. > _______________________________________________ > 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