[jboss-jira] [JBoss JIRA] Commented: (JBRULES-1572) sometimes getting ClassFieldExtractor error

[Mark Proctor (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBRULES-1572?page=comments#action_12411683 ] 
            
Mark Proctor commented on JBRULES-1572:
---------------------------------------

I've created the following unit test, based of your example:
    public void testMultiThreadOnSingleSession() throws Exception {
        String str = "package org.drools.test\n" +
        "import org.drools.Person\n" +
        "rule \"Auto Retract\"" +
        "when\n" +
        "    person:Person()\n" +
        "then\n" +
        "    retract(person);\n" +
        "end\n";
    
        RuleBase ruleBase = RuleBaseFactory.newRuleBase();
        PackageBuilder builder = new PackageBuilder();
        builder.addPackageFromDrl(new StringReader( str ) );
        Package pkg = builder.getPackage();
        ruleBase.addPackage(pkg);
        final WorkingMemory workingMemory = ruleBase.newStatefulSession();
        workingMemory.addEventListener(new DebugAgendaEventListener());

        Runnable runnable = new Runnable() {
            public void run() {
                while (true) {
                    workingMemory.insert(new Person( "bobba fet", 35));
                    workingMemory.fireAllRules();
                }
            }
        };

        Thread thread1 = new Thread(runnable, "thread1");
        Thread thread2 = new Thread(runnable, "thread2");
        thread1.start();
        thread2.start();        
        
        Thread.sleep( 15000 );
    }


However I'm not able to reproduce the problem, on my single cpu laptop. Is this a problem that only becomes visible on multiple cpus?

> sometimes getting ClassFieldExtractor error
> -------------------------------------------
>
>                 Key: JBRULES-1572
>                 URL: http://jira.jboss.com/jira/browse/JBRULES-1572
>             Project: JBoss Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>    Affects Versions: 5.0.0-M1, 4.0.4, 4.0.7
>            Reporter: Ming Fang
>         Assigned To: Mark Proctor
>         Attachments: Foo.java, rule.drl, Test.java, Test.java
>
>
> Caused by: java.lang.NullPointerException
> 	at org.drools.base.com.ml.ax.ModelValue10285014$getModelValue.getDoubleValue(Unknown Source)
> 	at org.drools.base.ClassFieldExtractor.getDoubleValue(ClassFieldExtractor.java:191)
> 	at org.drools.rule.Declaration.getDoubleValue(Declaration.java:281)
> 	at com.ml.ax.drools.Rule_Quote_0ConsequenceInvoker.evaluate(Rule_Quote_0ConsequenceInvoker.java:17)
> 	at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:586)
> This only happens sometimes but it completely breaks my program.

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