[jboss-jira] [JBoss JIRA] (JBRULES-3388) KnowledgeAgent custom classloader not working for PKG resources
Esteban Aliverti (JIRA)
jira-events at lists.jboss.org
Tue Feb 21 12:41:37 EST 2012
[ https://issues.jboss.org/browse/JBRULES-3388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12669658#comment-12669658 ]
Esteban Aliverti commented on JBRULES-3388:
-------------------------------------------
While working on this issue we discussed the 2 ways you have today to use a custom ClassLoader in a KAgent:
1.- Using a kbuilderConfig (like the example above)
2.- Using the same CL the provided kbase is using: adding "drools.agent.useKBaseClassLoaderForCompiling"=>"true" in the agent's configuration object.
Today, both ways work fine when you are dealing with "plain" resources like DRL, DSL, etc, but fail when dealing with binary packages (this is what this issue is all about).
Solving this issue using approach number 1 would make us to change some of the drools-api classes, and we prefer not to do that. Even more, approach number 1 is basically a subset of approach number 2 so we are deciding whether we leave it at all or not.
I will propose a solution to this issue but only for approach number 2. I will also state in the documentation that approach number 1 is discouraged as a way to use a custom CL for "plain" resources and that it DOES NOT even work for binary packages.
> KnowledgeAgent custom classloader not working for PKG resources
> ---------------------------------------------------------------
>
> Key: JBRULES-3388
> URL: https://issues.jboss.org/browse/JBRULES-3388
> Project: Drools
> Issue Type: Bug
> Security Level: Public(Everyone can see)
> Components: drools-core
> Affects Versions: 5.3.1.Final
> Environment: Windows 7, Java7-5, JBoss AS7.1
> Reporter: Herman Post
> Assignee: Mark Proctor
> Labels: drools-core
>
> I believe there may be a bug when trying to use a custom class loader with the KnowledgeAgent and the KnowledgeBuilderConfiguration, and when the ChangeSet is a PKG resource.
> I have been trying to get the knowledge-agent-classloader sample from the new Drools Cookbook to work with a PKG resource. The sample works fine for a DRL resource, but when I convert it to use my fact jar, and a PKG resource containing my rules, which I downloaded from Guvnor, it throws a ClassNotFoundException for my fact model. If I put my fact model in the classpath, the error goes away and my rules can be added to the KnowledgeAgent and run correctly. Following is the code from the sample that I have converted, and I have attached a zip file with a complete project demonstrating the problem. Also, I can get my rules and fact model to work if I use a DRL ChangeSet.knowledge-agent-classloader.zip
> URL modelJarURL = getClass().getResource("Patient-1.0.jar");
> URLClassLoader customURLClassloader = new URLClassLoader(new URL[] {modelJarURL });
> KnowledgeBuilderConfiguration kbuilderConfig = KnowledgeBuilderFactory.newKnowledgeBuilderConfiguration(null,
> customURLClassloader);
> KnowledgeBaseConfiguration kbaseConfig = KnowledgeBaseFactory.newKnowledgeBaseConfiguration(null, customURLClassloader);
> KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(kbaseConfig);
> KnowledgeAgentConfiguration aconf = KnowledgeAgentFactory.newKnowledgeAgentConfiguration();
> KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent("test", kbase, aconf, kbuilderConfig);
> // kagent.applyChangeSet(new ClassPathResource("change-set.xml", getClass())); // this goes with model.jar
> // kagent.applyChangeSet(new ClassPathResource("drl-change-set.xml", getClass())); // this goes with Patient.jar
> kagent.applyChangeSet(new ClassPathResource("pkg-change-set.xml", getClass())); // this goes with Patient.jar
> return kagent.getKnowledgeBase();
> Following is the stack trace from the error:
> java.lang.NullPointerException
> at org.drools.impl.KnowledgeBaseImpl.addKnowledgePackages(KnowledgeBaseImpl.java:148)
> at org.drools.agent.impl.KnowledgeAgentImpl.addResourcesToKnowledgeBase(KnowledgeAgentImpl.java:1016)
> at org.drools.agent.impl.KnowledgeAgentImpl.rebuildResources(KnowledgeAgentImpl.java:785)
> at org.drools.agent.impl.KnowledgeAgentImpl.buildKnowledgeBase(KnowledgeAgentImpl.java:657)
> at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:190)
> at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:169)
> at drools.cookbook.chapter02.KnowledgeAgentClassloaderTest.createKnowledgeBase(KnowledgeAgentClassloaderTest.java:59)
> at drools.cookbook.chapter02.KnowledgeAgentClassloaderTest.customClassloaderTest(KnowledgeAgentClassloaderTest.java:30)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
> at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
> at java.lang.reflect.Method.invoke(Unknown Source)
> at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:59)
> at org.junit.internal.runners.MethodRoadie.runTestMethod(MethodRoadie.java:98)
> at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:79)
> at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:87)
> at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:77)
> at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42)
> at org.junit.internal.runners.JUnit4ClassRunner.invokeTestMethod(JUnit4ClassRunner.java:88)
> at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
> at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
> at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
> at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
> at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
> at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
> at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
> I have been having the exact same problem when trying to use a custom class loader with just a KnowldegeBuilder and no KnowledgeAgent.
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