As suggested, I wrote some tests based on methods defined in the given class. That is, I extend from CommonTestMethodBase and used "loadKnowledgeBaseFromString(str)" to define the base for my KieSession. I was unable to reproduce the exception. I went through several cycles altering initializations, stripping down the rule, so forth but still to no avail.

Some of the steps I followed:

- Eliminate test harness. I added a main in my test class and simply instantiated that class and called the method directly.

- Executed in different environment. Changed from Intellij Idea IDE, to Eclipse IDE. Have not tried command line.

- In my application, I create the declared class externally and inject it into the engine The test method, on the other hand, injects the declared class via a high salience "init" rule. As such, I tried same approach in my application.

- In my application, removed all other rules, global, unused declarations. Further, I pruned down the offending rule to rudimentary instructions.

I have yet to dive into the drools/kie code to identify the differences, if any, between the test and application engine and rule initialization paths. Before I do, are there any suggestions on what other route I might take?

Thank you,

Roger

On Sat, May 10, 2014 at 11:06 AM, Mark Proctor <mproctor@codehaus.org> wrote:

We have a number of unit tests for expressions:
https://github.com/droolsjbpm/drools/blob/master/drools-compiler/src/test/java/org/drools/compiler/integrationtests/TimerAndCalendarTest.java

Could you add a unit test to demonstrate your problem, and submit it as a pull request?
http://docs.jboss.org/drools/release/5.5.0.Final/droolsjbpm-introduction-docs/html/gettingstarted.html

Mark

On 7 May 2014, at 21:36, rogerL <roger@precipicetech.com> wrote:

> Hello,
>
> I'm encountering an NPE when attempting to use and expression timer in my
> rule.
> env:
> Drools 6.0.1.Final
> OS Maverick
> IDE Intellij Idea
> Java 7
>
> Given the ebb and flow nature of the facts in the system, we want to be able
> to control the cycles dynamically. Hence the desire to use the expression
> timer.
> The expression that I tried is based on the 6.0.1 documentation.
> That is, something of the form *Timer(expr: $d, $p)*
> In an effort to get beyond the NPE, I tried playing around with the
> parameters by using combinations of both longs and appropriately formatted
> strings (e.g. 10s, 1m, etc), and using only the delay.
> I saw mention that a semicolon should follow the expression. That equally
> failed.
> The interval and cron timer variations, however, both work.
>
>
> The .drl and exception are:
>
> declare SystemControlData
> isEnabled : boolean = false
> delay : long = 30
> period : long = 60000
> maxCallQueueDepth : int = 1
> end
>
>
> rule "If the system is enabled start campaign check at specified interval"
> agenda-group "system_criteria"
> // auto-focus true
> salience 20
> // timer( expr: $d, $p ) throws NPE
> // timer( expr: $d; ) throws NPE
> timer(cron:0/5 * * * * ?)
> when
> SystemControlData(isEnabled==true, $d: delay, $p:period,
> maxCallQueueDepth>0)
> then
> drools.setFocus( "campaign_criteria" );
> end
>
>
>
> Exception in thread "SimpleAsyncTaskExecutor-1"
> java.lang.NullPointerException
> at
> org.drools.core.base.mvel.MVELCompilationUnit.createFactory(MVELCompilationUnit.java:262)
> at
> org.drools.core.base.mvel.MVELCompilationUnit.getFactory(MVELCompilationUnit.java:276)
> at
> org.drools.core.base.mvel.MVELObjectExpression.getValue(MVELObjectExpression.java:76)
> at org.drools.core.time.TimeUtils.evalTimeExpression(TimeUtils.java:140)
> at
> org.drools.core.time.impl.ExpressionIntervalTimer.createTrigger(ExpressionIntervalTimer.java:151)
> at
> org.drools.core.phreak.PhreakTimerNode.createTrigger(PhreakTimerNode.java:260)
> at
> org.drools.core.phreak.PhreakTimerNode.scheduleLeftTuple(PhreakTimerNode.java:230)
> at
> org.drools.core.phreak.PhreakTimerNode.doLeftInserts(PhreakTimerNode.java:93)
> at org.drools.core.phreak.PhreakTimerNode.doNode(PhreakTimerNode.java:69)
> at
> org.drools.core.phreak.RuleNetworkEvaluator.innerEval(RuleNetworkEvaluator.java:357)
> at
> org.drools.core.phreak.RuleNetworkEvaluator.outerEval(RuleNetworkEvaluator.java:161)
> at
> org.drools.core.phreak.RuleNetworkEvaluator.evaluateNetwork(RuleNetworkEvaluator.java:116)
> at
> org.drools.core.phreak.RuleExecutor.reEvaluateNetwork(RuleExecutor.java:200)
> at
> org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:67)
> at
> org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:935)
> at
> org.drools.core.common.DefaultAgenda.fireUntilHalt(DefaultAgenda.java:1160)
> at
> org.drools.core.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:1002)
> at
> org.drools.core.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:978)
> at
> org.drools.core.impl.StatefulKnowledgeSessionImpl.fireUntilHalt(StatefulKnowledgeSessionImpl.java:273)
>
>
>
> --
> View this message in context: http://drools.46999.n3.nabble.com/Expression-Timer-NPE-Drools-6-0-1-Final-tp4029469.html
> Sent from the Drools: Developer (committer) mailing list mailing list archive at Nabble.com.
> _______________________________________________
> rules-dev mailing list
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Roger Lefebvre

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(e) roger@precipicetech.com

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