8:24 a.m.
Malory,
I'm replying here, rather than to your private email. We are an open source community,
by asking these questions publicly it ensures all can participate and learn, and the
conversations are archived for searching.
Your line numbers seem off. I'm looking at line 39 in
DefaultConsequenceExceptionHandler:
https://github.com/droolsjbpm/drools/blob/5.4.x/drools-core/src/main/java...
Line 39 is the last argument of the method declaration. Also the only thing that could
cause null pointer while handleException is if you were to pass a null Activation.
I think you are trying to do this too high up, where there is all sorts of thread safety
issues you are exposing by putting Runnable around fireNextItem. There is shared states
that those threads will access, which will cause problems.
Better to do it when the consequence is invoked directly:
activation.getConsequence().evaluate( this.knowledgeHelper, this.workingMemory );
Mark
On 10 Mar 2013, at 08:05, gmalathi.in(a)gmail.com wrote:
Hi Mark,
I have tried to change the source code of DefaultAgenda.Java by adding the code below:
//drools orginial sequential code
/*
while ( continueFiring( fireLimit ) && fireNextItem( agendaFilter ) ) {
fireCount++;
fireLimit = updateFireLimit( fireLimit );
this.workingMemory.executeQueuedActions();
}
*/
//code with concurrency
InternalAgendaGroup myGroup = (InternalAgendaGroup) getNextFocus();
fireCount = myGroup.size();
for(int i =0; i< fireCount; ++i)
{
new Thread(new Runnable(){
public void run()
{
fireNextItem( agendaFilter );
}
}).start();
}
I am getting an Errorjava.lang.NullPointerException because my code flow is going to
consequenceExceptionHandler ! = null exception.
else if ( this.consequenceExceptionHandler != null ) {
this.consequenceExceptionHandler.handleException( activation,
this.workingMemory.getKnowledgeRuntime(),
e );
Could you kindly help me with this?
I am pasting the exception below and I am using Drools 5.4 Final version.
In DA: [Activation rule=Rule 1, act#=0, salience=0, tuple=[fact
0:0:1773684356:1306428912:0:DEFAULT:org.drools.reteoo.InitialFactImpl@4dde85f0]
]
Exception in thread "Thread-1" Exception in thread "Thread-0"
Exception executing consequence for rule "Rule 1" in defaultpkg:
java.lang.NullPointerException
In DA WM: org.drools.impl.StatefulKnowledgeSessionImpl@542487b1
In DA Errorjava.lang.NullPointerException
In DA: [Activation rule=Rule 2, act#=1, salience=0, tuple=[fact
0:0:1773684356:1306428912:0:DEFAULT:org.drools.reteoo.InitialFactImpl@4dde85f0]
]
In DA WM: org.drools.impl.StatefulKnowledgeSessionImpl@542487b1
In DA Errorjava.lang.NullPointerException
at
org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1208)
at org.drools.common.DefaultAgenda$1.run(DefaultAgenda.java:1471)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1272)
... 3 more
Exception executing consequence for rule "Rule 2" in defaultpkg:
java.lang.NullPointerException
at
org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1208)
at org.drools.common.DefaultAgenda$1.run(DefaultAgenda.java:1471)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1272)
... 3 more
Thanks a lot for the help.
Regards,
Malory
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Mark Proctor