[rules-users] Can't execute rules twice with a second classloader

[Aaron Dixon]

I am trying to sequentially perform two rules executions using two
different classloaders in the same VM. I create completely new state
for each execution, yet I still fail on the second execution. I
believe this has to do with some internal static cached state that
JBossRules is maintaining. A snippet of the code and exeception are
shown in this email.

    public void demo() throws Exception {
        // Save original classloader
        ClassLoader original = Thread.currentThread().getContextClassLoader();

        // Create Classloader 1 with parent of original
        FooClassLoader loader1 = new FooClassLoader(original);
        Thread.currentThread().setContextClassLoader(loader1);
        testRules();

        // Success so far...

        // Create Classloader 2 with parent of original
        FooClassLoader loader2 = new FooClassLoader(original);
        Thread.currentThread().setContextClassLoader(loader2);
        testRules();

        // Never make it to here.

        // Restore
        Thread.currentThread().setContextClassLoader(original);
    }

    private void testRules() throws Exception {
        PackageBuilder builder = new PackageBuilder();
        Package pkg = buildPackage(new String[] { "Foo.drl" }, builder);
        RuleBase base = RuleBaseFactory.newRuleBase();
        base.addPackage(pkg);
        StatelessSession session = base.newStatelessSession();
        final ClassLoader loader =
Thread.currentThread().getContextClassLoader();
        Object inst = loader.loadClass("com.foo.Foo").newInstance();
        session.execute(new Object[] { inst });
    }



Exception in thread "main" java.lang.ClassCastException:
adixon.prototype.rules.classloader.demo.copy.FooShadowProxy
	at org.drools.base.adixon.prototype.rules.classloader.demo.copy.Foo$getName.getValue(Unknown
Source)
	at org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:94)
	at org.drools.base.evaluators.StringFactory$StringEqualEvaluator.evaluate(StringFactory.java:85)
	at org.drools.rule.LiteralRestriction.isAllowed(LiteralRestriction.java:61)
	at org.drools.rule.LiteralConstraint.isAllowed(LiteralConstraint.java:82)
	at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:121)
	at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:20)
	at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:159)
	at org.drools.reteoo.Rete.assertObject(Rete.java:175)
	at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:190)
	at org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:70)
	at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:772)
	at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:584)
	at org.drools.reteoo.ReteooStatelessSession.execute(ReteooStatelessSession.java:63)
	at adixon.prototype.rules.classloader.demo.copy.Driver.testRules(Driver.java:47)
	at adixon.prototype.rules.classloader.demo.copy.Driver.go(Driver.java:33)
	at adixon.prototype.rules.classloader.demo.copy.Driver.main(Driver.java:17)