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<div dir="ltr"><font face="Tahoma" color="#000000" size="2">I can give this a shot, but the reason why you suggest this is not obvious to me.
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<div dir="ltr"><font face="tahoma" size="2">Have you encountered this problem yourself?</font></div>
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<div dir="ltr"><font face="tahoma" size="2">-Jason</font></div>
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<font face="Tahoma" size="2"><b>From:</b> rules-users-bounces@lists.jboss.org [rules-users-bounces@lists.jboss.org] On Behalf Of Anstis, Michael (M.) [manstis1@ford.com]<br>
<b>Sent:</b> Monday, March 10, 2008 5:06 AM<br>
<b>To:</b> Rules Users List<br>
<b>Subject:</b> RE: [rules-users] Interesting null pointer exception when inserting afact.<br>
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<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2">I'm no expert but recall there can be problems running "long running" (subjective) code from AWT's worker thread.</font></span></div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2">I thought it was good practice to run your "application code" in a worker thread. This was the first google hit I had on the matter. </font></span></div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2"><a href="http://www.cs.helsinki.fi/u/vihavain/k03/Java/JavathreadsandGUI.html" target="_blank">http://www.cs.helsinki.fi/u/vihavain/k03/Java/JavathreadsandGUI.html</a></font></span></div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2">Cheers,</font></span></div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="450020310-10032008"><font face="Arial" color="#0000ff" size="2">Mike</font></span></div>
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<font face="Tahoma" size="2"><b>From:</b> rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org]
<b>On Behalf Of </b>Edson Tirelli<br>
<b>Sent:</b> 08 March 2008 13:15<br>
<b>To:</b> Rules Users List<br>
<b>Subject:</b> Re: [rules-users] Interesting null pointer exception when inserting afact.<br>
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Jason,<br>
<br>
Can you please isolate and show us the rule that is creating the problem? It is happening either in a eval() statement or in a nested property access.<br>
<br>
[]s<br>
Edson<br>
<br>
<div><span class="gmail_quote">2008/3/7, Jason Partyka <<a href="mailto:Jason.Partyka@hightowerinc.com">Jason.Partyka@hightowerinc.com</a>>:</span>
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Hi,<br>
<br>
This is in relation to drools 4.0.4<br>
<br>
I have an interesting problem. I am getting a null pointer exception when I am inserting a fact into a StatefulSession object. What is odd about this NPE is that, as far as I can tell (and I have inserted a breakpoint right before I insert the fact) that all
the properties in the object are initialized, and there are no rules accessing any thing that could be null.<br>
<br>
So here's my exception trace (just first few lines to get context):<br>
<br>
Exception in thread "AWT-EventQueue-0" org.drools.RuntimeDroolsException: java.lang.NullPointerException<br>
at org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:76)<br>
at org.drools.reteoo.EvalConditionNode.assertTuple(EvalConditionNode.java:145)<br>
at org.drools.reteoo.SingleTupleSinkAdapter.createAndPropagateAssertTuple(SingleTupleSinkAdapter.java:55)<br>
at org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:116)<br>
at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:22)<br>
at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:153)<br>
at org.drools.reteoo.Rete.assertObject(Rete.java:177)<br>
at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192)<br>
at org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:71)<br>
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:886)<br>
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:858)<br>
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:659)<br>
at com.hightower.drools.executablerules.Rules.setTemplate(Rules.java:112)<br>
....<br>
Caused by: java.lang.NullPointerException<br>
at org.drools.base.mvel.MVELEvalExpression.evaluate(MVELEvalExpression.java:39)<br>
at org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:72)<br>
... 39 more<br>
<br>
<br>
(that setTemplate method is not a drools template)<br>
<br>
Any ideas?<br>
<br>
Thanks,<br>
Jason<br>
<br>
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<br>
-- <br>
Edson Tirelli<br>
JBoss Drools Core Development<br>
Office: +55 11 3529-6000<br>
Mobile: +55 11 9287-5646<br>
JBoss, a division of Red Hat @ <a href="http://www.jboss.com" target="_blank">www.jboss.com</a>
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