5:09 p.m.
Well, I've downloaded the source, and it appears that it is occuring in the
org.mvel.MVELRuntime class, method execute(). My equals token ("==") is being
properly recognized, and converted to its integer representation (10). However, in a block
with switch (operator), the org.mvel.Operator.EQUAL token does not appear, so the
execute() method returns a null value because nothing is ever evaluated.
I've even verified that null is being returned from the execute method.
I stepped back out to the line (in org.mvel.CompiledExpression,java)
return handleParserEgress(execute(false, this, staticContext, factory),
returnBigDecimal);
and then stepped into handleParserEgress and the first parameter, which is the return
value from execute() is null!
Any ideas?
Thanks,
Jason
-----------
From: rules-users-bounces(a)lists.jboss.org [rules-users-bounces(a)lists.jboss.org] On Behalf
Of Mark Proctor [mproctor(a)codehaus.org]
Sent: Wednesday, March 12, 2008 2:28 PM
To: Rules Users List
Subject: Re: [rules-users] Interesting null pointer exception when inserting afact.
Jason Partyka wrote:
It looks like the bug is still in there.
I am attempting to resolve it myself, but in order to do so I need to go into the MVEL
code, but the mvel jar that is included as part of the drools classpath container (within
eclipse) is just mvel14.jar. So I'm not sure where the source is or what version of
MVEL source I should be attaching. I realize that the source-location thing is just an
Eclipse issue, but I thought I'd let you know right away that it looks like it's
still there.
We strip jar version numbers to make deployment with Eclipse easier. If you look at parent
pom.xml it will tell you the version of MVEL used.
Anywhere you can point me to that would help with making sure I'm looking the right
code.
Thanks,
Jason
From: rules-users-bounces(a)lists.jboss.org [rules-users-bounces(a)lists.jboss.org] On Behalf
Of Mark Proctor [mproctor(a)codehaus.org]
Sent: Monday, March 10, 2008 8:17 AM
To: Rules Users List
Subject: Re: [rules-users] Interesting null pointer exception when inserting afact.
please check with 4.0.x, which will be in 4.0.5 this week, and let us know if this is
fixed or not. But hurry we are releasing 4.0.5 very soon:
http://anonsvn.labs.jboss.com/labs/jbossrules/branches/4.0.x/
Mark
Jason Partyka wrote:
I can give this a shot, but the reason why you suggest this is not obvious to me.
Have you encountered this problem yourself?
-Jason
From: rules-users-bounces(a)lists.jboss.org [rules-users-bounces(a)lists.jboss.org] On Behalf
Of Anstis, Michael (M.) [manstis1(a)ford.com]
Sent: Monday, March 10, 2008 5:06 AM
To: Rules Users List
Subject: RE: [rules-users] Interesting null pointer exception when inserting afact.
I'm no expert but recall there can be problems running "long running"
(subjective) code from AWT's worker thread.
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.
http://www.cs.helsinki.fi/u/vihavain/k03/Java/JavathreadsandGUI.html
Cheers,
Mike
From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On
Behalf Of Edson Tirelli
Sent: 08 March 2008 13:15
To: Rules Users List
Subject: Re: [rules-users] Interesting null pointer exception when inserting afact.
Jason,
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.
[]s
Edson
2008/3/7, Jason Partyka <Jason.Partyka(a)hightowerinc.com>:
Hi,
This is in relation to drools 4.0.4
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.
So here's my exception trace (just first few lines to get context):
Exception in thread "AWT-EventQueue-0" org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:76)
at org.drools.reteoo.EvalConditionNode.assertTuple(EvalConditionNode.java:145)
at
org.drools.reteoo.SingleTupleSinkAdapter.createAndPropagateAssertTuple(SingleTupleSinkAdapter.java:55)
at org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:116)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:22)
at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:153)
at org.drools.reteoo.Rete.assertObject(Rete.java:177)
at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192)
at org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:71)
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:886)
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:858)
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:659)
at com.hightower.drools.executablerules.Rules.setTemplate(Rules.java:112)
....
Caused by: java.lang.NullPointerException
at org.drools.base.mvel.MVELEvalExpression.evaluate(MVELEvalExpression.java:39)
at org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:72)
... 39 more
(that setTemplate method is not a drools template)
Any ideas?
Thanks,
Jason
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--
Edson Tirelli
JBoss Drools Core Development
Office: +55 11 3529-6000
Mobile: +55 11 9287-5646
JBoss, a division of Red Hat @ www.jboss.com
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