Manuel,<br><br>I have reported this (or a very similar) problem <a href="https://issues.jboss.org/browse/JBRULES-2887">https://issues.jboss.org/browse/JBRULES-2887</a> with a small example to reproduce.<br><br>The stack trace is not identical, so please try to reproduce this with a small test case; it is bound to happen with a rule (Test Negativo Alarma Acceso Portal Ubicacion UM) that modifies some fact that is used in an "accumulate" phrase, (If this pattern is different from the one I gave, I'll raise the issue priority to "critical".)<br>
<br>Cheers<br>Wolfgang<br><br><br><div class="gmail_quote">2011/3/30 Manuel Ortiz <span dir="ltr"><<a href="mailto:manuel.ortizramos@gmail.com">manuel.ortizramos@gmail.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hello all!<div><br></div><div>I am new in Drools but day by day, test by test, I think I get a bit more knowledge of how the rule engine works from user point of view. I've been adding rules to an alarm system, increasing the complexity and functionality in several steps. Unfortunately in the last step I found the following NullPointerException inside the rule engine...</div>
<div><br></div><div><div>java.lang.NullPointerException</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.AccumulateNode.getFirstMatch(AccumulateNode.java:967)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.AccumulateNode.modifyLeftTuple(AccumulateNode.java:329)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateModifyChildLeftTuple(SingleLeftTupleSinkAdapter.java:239)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.AccumulateNode.evaluateResultConstraints(AccumulateNode.java:640)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.AccumulateNode.assertObject(AccumulateNode.java:270)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:312)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:460)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:428)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:160)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:460)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:428)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:263)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:172)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1442)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1349)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:183)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:196)</div><div><span style="white-space: pre-wrap;"> </span>at es.simcasva.alarmas.rules.Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0.defaultConsequence(Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0.java:18)</div>
<div><span style="white-space: pre-wrap;"> </span>at es.simcasva.alarmas.rules.Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0DefaultConsequenceInvoker.evaluate(Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0DefaultConsequenceInvoker.java:44)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:917)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:856)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1071)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:785)</div>
<div><span style="white-space: pre-wrap;"> </span>at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:751)</div><div><span style="white-space: pre-wrap;"> </span>at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:218)</div>
</div><div><br></div><div>I've been trying to find the problem, and found a strange interaction between three rules that makes the null pointer to appear. The alarm system has many rules now and it is difficult to simplify the scenario, so I just would like to know what is the funcion of AccumulateNode object in order to have an idea of the NullPointerException possible cause.</div>
<div><br></div><div>Can anyone help me?</div><div><br></div><div>Thank you in advance for your time.</div><div><br></div><div>Regards,</div><div><br></div><font color="#888888"><div>Manuel Ortiz.</div><div><br></div>
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<br></blockquote></div><br>