[jboss-jira] [JBoss JIRA] (DROOLS-1158) NullpointerException when trying to reuse KnowledgePackage into a new KnowledgeBase

ti swei (JIRA) issues at jboss.org
Thu Aug 2 06:59:00 EDT 2018


    [ https://issues.jboss.org/browse/DROOLS-1158?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13613718#comment-13613718 ] 

ti swei commented on DROOLS-1158:
---------------------------------

Hi Matteo Mortari, I met same problem with Juan Carlos Garcia. My drools version is 6.5.0 Final.  I tried to solve the problem, but I didn't succeed. Matteo Mortari, can you give me some help, the following is my exception message:
java.lang.NullPointerException: null
	at org.drools.core.rule.constraint.MvelConstraint.equals(MvelConstraint.java:617)
	at org.drools.core.reteoo.AlphaNode.internalEquals(AlphaNode.java:200)
	at org.drools.core.common.BaseNode.thisNodeEquals(BaseNode.java:193)
	at org.drools.core.reteoo.SingleObjectSinkAdapter.getMatchingNode(SingleObjectSinkAdapter.java:136)
	at org.drools.core.reteoo.builder.BuildUtils.attachNode(BuildUtils.java:120)
	at org.drools.core.reteoo.builder.PatternBuilder.buildAlphaNodeChain(PatternBuilder.java:331)
	at org.drools.core.reteoo.builder.PatternBuilder.attachAlphaNodes(PatternBuilder.java:312)
	at org.drools.core.reteoo.builder.PatternBuilder.attachPattern(PatternBuilder.java:129)
	at org.drools.core.reteoo.builder.PatternBuilder.build(PatternBuilder.java:77)
	at org.drools.core.reteoo.builder.GroupElementBuilder$AndBuilder.build(GroupElementBuilder.java:108)
	at org.drools.core.reteoo.builder.GroupElementBuilder.build(GroupElementBuilder.java:68)
	at org.drools.core.reteoo.builder.ReteooRuleBuilder.addSubRule(ReteooRuleBuilder.java:161)
	at org.drools.core.reteoo.builder.ReteooRuleBuilder.addRule(ReteooRuleBuilder.java:133)
	at org.drools.core.reteoo.ReteooBuilder.addRule(ReteooBuilder.java:106)
	at org.drools.core.impl.KnowledgeBaseImpl.addRule(KnowledgeBaseImpl.java:1586)
	at org.drools.core.impl.KnowledgeBaseImpl.addRule(KnowledgeBaseImpl.java:1566)
	at org.drools.compiler.builder.impl.KnowledgeBuilderImpl.compileAllRules(KnowledgeBuilderImpl.java:1004)
	at org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.buildRules(CompositeKnowledgeBuilderImpl.java:264)
	at org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.buildPackages(CompositeKnowledgeBuilderImpl.java:122)
	at org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.build(CompositeKnowledgeBuilderImpl.java:105)
	at org.drools.compiler.kie.builder.impl.KieContainerImpl.rebuildAll(KieContainerImpl.java:449)
	at org.drools.compiler.kie.builder.impl.KieContainerImpl.updateKBase(KieContainerImpl.java:311)
	at org.drools.compiler.kie.builder.impl.KieContainerImpl.access$000(KieContainerImpl.java:88)
	at org.drools.compiler.kie.builder.impl.KieContainerImpl$1.run(KieContainerImpl.java:255)
	at org.drools.core.impl.KnowledgeBaseImpl.enqueueModification(KnowledgeBaseImpl.java:735)
	at org.drools.compiler.kie.builder.impl.KieContainerImpl.update(KieContainerImpl.java:252)
	at org.drools.compiler.kie.builder.impl.KieContainerImpl.updateToVersion(KieContainerImpl.java:196)
	at com.zte.vmaster.correlation.engine.manager.DroolsEngine.deployRule(DroolsEngine.java:274)


my code is as follows :

{code:java}
public class DroolsEngineCode {

    private KieBase kieBase;
    private KieSession kieSession;
    private KieContainer kieContainer;
    private KieFileSystem kfs;
    private KieServices ks;
    private KieResources resources;
    private KieBuilder kieBuilder;
    private KieRepository kieRepository;
    private ReleaseId releaseId;

    @PreDestroy
    private void stop() {
        this.kieSession.dispose();
    }

    @PostConstruct
    private void initEngineParameter() throws Exception {
        this.ks = KieServices.Factory.get();
        this.resources = ks.getResources();
        this.kieRepository = ks.getRepository();
        this.releaseId = kieRepository.getDefaultReleaseId();
        this.kfs = createKieFileSystemWithKProject(ks);
        this.kieBuilder = ks.newKieBuilder(kfs).buildAll();
        this.kieContainer = ks.newKieContainer(this.releaseId);

        this.kieBase = kieContainer.getKieBase();
        this.kieSession = kieContainer.newKieSession();
    }

    public synchronized void deployRule(String ruleContent) throws Exception {
        if (JudgeNullUtil.isEmpty(ruleContent)) {
            throw new NullPointerException();
        }

        StringReader reader = new StringReader(ruleContent);

        KieModule kieModule = createKieJar(ks, this.resources.newReaderResource(reader, "UTF-8")
                .setResourceType(ResourceType.DRL));

        kieRepository.addKieModule(kieModule);

        kieContainer.updateToVersion(releaseId);
        kieSession.fireAllRules();
    }

    public synchronized void undeployRule(String packageName, Locale locale)
            throws CorrelationException {
        kieBase.removeKiePackage(packageName);
    }

    private KieFileSystem createKieFileSystemWithKProject(KieServices ks) {
        KieModuleModel kieModuleModel = ks.newKieModuleModel();
        KieBaseModel kieBaseModel = kieModuleModel.newKieBaseModel("KBase")
                .addPackage("rules")
                .setDefault(true)
                .setEqualsBehavior(EqualityBehaviorOption.EQUALITY)
                .setEventProcessingMode(EventProcessingOption.STREAM);
        kieBaseModel.newKieSessionModel("KSession")
                .setDefault( true )
                .setType( KieSessionModel.KieSessionType.STATEFUL )
                .setClockType( ClockTypeOption.get("realtime") );
        KieFileSystem kfs = ks.newKieFileSystem();
        kfs.writeKModuleXML(kieModuleModel.toXML());
        return kfs;
    }

    private KieModule createKieJar(KieServices ks, Resource resource) throws Exception {
        kfs.write("src/main/resources/rules/rule.drl", resource);
        kieBuilder = ks.newKieBuilder(kfs);
        if (kieBuilder.getResults().hasMessages(Message.Level.ERROR)) {
            throw new Exception();
        }
        return kieBuilder.getKieModule();
    }
}
{code}


> NullpointerException when trying to reuse KnowledgePackage into a new KnowledgeBase
> -----------------------------------------------------------------------------------
>
>                 Key: DROOLS-1158
>                 URL: https://issues.jboss.org/browse/DROOLS-1158
>             Project: Drools
>          Issue Type: Bug
>    Affects Versions: 6.3.0.Final, 6.4.0.Final
>            Reporter: Juan Carlos Garcia
>            Assignee: Matteo Mortari
>         Attachments: drools-reusepackage.tar, screenshot-1.png
>
>
> Having a set of DecisionTables which KnowledgePackages are cached in our application, after we detect a change in any of those XLS files, we build a KnowledgePackages from it, and then try to create a new KnowledgeBase with the new KnowledgePackages + the rest of the cached one that that were not modified, but it fails with a NPE internally in Drools (6.3.0 and 6.4.0)
> This is not a problem for the drools version (6.0.1.Final) that we currently uses using in production.
> After debugging and putting a breakpoint into the *MvelConstraint.java:619*,  it shows that it is trying to look for a packageName which hasn't being loaded yet in the new kbase (but belong to others XLS).
> I have attached a project with a testcase that shows the problem, it has 2 DecisionTable which i had to cut down a little bit (from our real files) and removes some sensitive information (replacing some of text with FOO-BAR).
> {code}
> java.lang.NullPointerException
>         at org.drools.core.rule.constraint.MvelConstraint.equals(MvelConstraint.java:619)
>         at org.drools.core.reteoo.AlphaNode.internalEquals(AlphaNode.java:199)
>         at org.drools.core.common.BaseNode.thisNodeEquals(BaseNode.java:194)
>         at org.drools.core.reteoo.CompositeObjectSinkAdapter.getMatchingNode(CompositeObjectSinkAdapter.java:531)
>         at org.drools.core.reteoo.builder.BuildUtils.attachNode(BuildUtils.java:121)
>         at org.drools.core.reteoo.builder.PatternBuilder.buildAlphaNodeChain(PatternBuilder.java:332)
>         at org.drools.core.reteoo.builder.PatternBuilder.attachAlphaNodes(PatternBuilder.java:313)
>         at org.drools.core.reteoo.builder.PatternBuilder.attachPattern(PatternBuilder.java:130)
>         at org.drools.core.reteoo.builder.PatternBuilder.build(PatternBuilder.java:78)
>         at org.drools.core.reteoo.builder.GroupElementBuilder$AndBuilder.build(GroupElementBuilder.java:108)
>         at org.drools.core.reteoo.builder.GroupElementBuilder.build(GroupElementBuilder.java:68)
>         at org.drools.core.reteoo.builder.ReteooRuleBuilder.addSubRule(ReteooRuleBuilder.java:161)
>         at org.drools.core.reteoo.builder.ReteooRuleBuilder.addRule(ReteooRuleBuilder.java:133)
>         at org.drools.core.reteoo.ReteooBuilder.addRule(ReteooBuilder.java:106)
>         at org.drools.core.impl.KnowledgeBaseImpl.addRule(KnowledgeBaseImpl.java:1567)
>         at org.drools.core.impl.KnowledgeBaseImpl.addRule(KnowledgeBaseImpl.java:1547)
>         at org.drools.core.impl.KnowledgeBaseImpl.internalAddPackages(KnowledgeBaseImpl.java:920)
>         at org.drools.core.impl.KnowledgeBaseImpl.access$000(KnowledgeBaseImpl.java:117)
>         at org.drools.core.impl.KnowledgeBaseImpl$1.run(KnowledgeBaseImpl.java:708)
>         at org.drools.core.impl.KnowledgeBaseImpl.enqueueModification(KnowledgeBaseImpl.java:716)
>         at org.drools.core.impl.KnowledgeBaseImpl.addPackages(KnowledgeBaseImpl.java:705)
>         at org.drools.core.impl.KnowledgeBaseImpl.addKnowledgePackages(KnowledgeBaseImpl.java:273)
>         at org.drools.impl.adapters.KnowledgeBaseAdapter.addKnowledgePackages(KnowledgeBaseAdapter.java:62)
>         at bug.demo.BugReloadableDecisionTableTest.addRuleSetToKnowledgeBase(BugReloadableDecisionTableTest.java:63)
>         at bug.demo.BugReloadableDecisionTableTest.testReuseKnowledgePackage(BugReloadableDecisionTableTest.java:53)
> {code}



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