[rules-users] Drools function not working with Javassist facts

[Wolfgang Laun]

Set-up of the classpath for compile and execute:

    ADDON=javassist/javassist-3.16.1-GA/javassist.jar
    root=/extra/drools-distribution-5.3.0.Final/binaries
    tag=5.3.0.Final
    export CLASSPATH=.:$root/drools-core-${tag}.jar:$root/knowledge-api-${tag}.jar:$root/drools-compiler-${tag}.jar:$root/antlr-2.7.7.jar:$root/antlr-3.3.jar:$root/antlr-runtime-3.3.jar:$root/mvel2-2.1.0.drools7.jar:$root/ecj-3.5.1.jar:/extra/quartz-1.8.3/quartz-1.8.3.jar:$root/drools-decisiontables-${tag}.jar:$root/drools-templates-${tag}.jar:$root/xstream-1.4.1.jar:$root/xmlpull-1.1.3.1.jar:$ADDON


// === dynamic/Main.java ================
package dynamic;

import java.io.IOException;

import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseConfiguration;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.conf.EventProcessingOption;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;

import dynamic.FactGenerator;

public class Main {

    void myCode () throws Exception {
        System.out.println ("myCode()");

        final Object obj = new FactGenerator ().getFact ();


        final KnowledgeBase knowledgeBase = createKnowledgeBase ();
        final StatefulKnowledgeSession session =
knowledgeBase.newStatefulKnowledgeSession ();
        try {
            session.insert (obj);
            System.out.println ("Firing rule...");
            final int count = session.fireAllRules ();
            System.out.println ("rules count: " + count);
        } finally {
            session.dispose ();
        }

    }

    private static KnowledgeBase createKnowledgeBase () {
        System.out.println ("DroolsInvokerServlet.createKnowledgeBase()");

        final KnowledgeBaseConfiguration config =
KnowledgeBaseFactory.newKnowledgeBaseConfiguration ();
        config.setOption (EventProcessingOption.STREAM);
        final KnowledgeBuilder builder =
KnowledgeBuilderFactory.newKnowledgeBuilder ();

        builder.add (ResourceFactory.newClassPathResource
("dynamic/testRule.drl"), ResourceType.DRL);
        if (builder.hasErrors ()) {
            throw new RuntimeException (builder.getErrors ().toString ());
        }
        final KnowledgeBase knowledgeBase =
KnowledgeBaseFactory.newKnowledgeBase (config);
        knowledgeBase.addKnowledgePackages (builder.getKnowledgePackages ());
        return knowledgeBase;
    }

    public static void main (final String[] args) throws Exception {
        Main m = new Main();
	m.myCode ();
    }
}

// === FactGenerator.java ====================
package dynamic;

import java.io.*;

import java.lang.reflect.Modifier;

import javassist.CannotCompileException;
import javassist.NotFoundException;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtField;
import javassist.CtMethod;
import javassist.CtNewMethod;

public class FactGenerator {

    static Class msgClass;

    public Object getFact () throws IOException, NotFoundException,
CannotCompileException, InstantiationException, IllegalAccessException
{

        if (msgClass != null) {
            return msgClass.newInstance ();
        } else {
            final ClassPool pool = ClassPool.getDefault ();
            CtClass msgCtClass = null;
            System.out.println ("creating new class...");
            msgCtClass = pool.makeClass ("drools.dynamic.Message");
            final CtField field = new CtField (CtClass.intType,
"Count", msgCtClass);
            field.setModifiers (Modifier.PRIVATE);
            msgCtClass.addField (field);

            final CtMethod getter = CtNewMethod.getter ("getCount", field);
            msgCtClass.addMethod (getter);

            final CtMethod setter = CtNewMethod.getter ("setCount", field);
            msgCtClass.addMethod (setter);

            msgCtClass.writeFile();

            msgClass = msgCtClass.toClass ();
            return msgClass.newInstance ();
        }
    }
}

import drools.dynamic.Message;

function void logMessage() {
	
}

// === testRule.drl =====================
rule "Hello World"
##	dialect "mvel"
	when
		$m : Message( count == 0 )
	then
		
		System.out.println("count: "+$m.getCount());
		logMessage();
		retract($m);
		
end







On 18/05/2012, Ayush <ayush.vatsyayan at alcatel-lucent.com> wrote:
> Thanks Laune, I tried executing it after adding msgCtClass.writeFile();
> but
> it's still throwing the same exception.
>
> If you could please share the version of lib files you are using along with
> the file with the changes?
>
> --
> View this message in context:
> http://drools.46999.n3.nabble.com/Drools-function-not-working-with-Javassist-facts-tp3996584p4000536.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
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