[rules-users] RE: JavaConsequenceBuilder.buildNullPointerException

Wed Oct 31 13:17:50 EDT 2007

Thank you so very much. Yes, changing the parse to handle this would be
very helpful.

________________________________

From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Edson Tirelli
Sent: Wednesday, October 31, 2007 12:32 PM
To: Rules Users List
Subject: Re: [rules-users] RE:
JavaConsequenceBuilder.buildNullPointerException

   Michael,

   The problem is you missed the "" on:

    $result.addPassedRule(leaders in same location);

    I will fix the parser code to not throw NPE for this anymore.

    Thanks,
      Edson

2007/10/31, Michael Fuller <mfuller at ihets.org>:

Sure. Thanks

package validActions;

import myPackage.domain.leader.LeaderImpl;

import myPackage.domain.location.LocationImpl;

import myPackage.domain.leader.LeaderTypeImpl;

import myPackage.rivoli.service.rules.RuleResult;

rule "leaders in same location"

salience 10

when

    $result : RuleResult(rulesPassed not contains "leaders in same
location")

    $loc : LocationImpl()

    $leaderName : String()

    $leader1 : LeaderImpl(name == $leaderName, location == $loc)

    $leader2 : LeaderImpl(name != $leaderName, this != $leader1,
location == $loc)

then

    $result.addPassedRule(leaders in same location);

    update($result);

end

rule "leaders king and heir"

salience 10

when

    $result : RuleResult(rulesPassed not contains "leaders king and
heir")

    $leaderName : String()

    $king : LeaderTypeImpl(name == "King")

    $heir : LeaderTypeImpl(name == "Heir")

    $leader1 : LeaderImpl(name == $leaderName, leaderType == $king)

    $leader2 : LeaderImpl(name != $leaderName, this != $leader1,
leaderType == $heir)

then

    $result.addPassedRule("leaders king and heir");

    update($result);

end

rule "leader in capital"

salience 10

when

    $result : RuleResult(rulesPassed not contains "leader in capital")

    $loc : LocationImpl(capital == true)

    $leader1 : LeaderImpl(location == $loc)

then

    $result.addPassedRule("leader in capital");

    update($result);

end

rule "leader in homeland"

salience 10

when

    $result : RuleResult(rulesPassed not contains "leader in homeland")

    $loc : LocationImpl(homeland == true)

    $leader1 : LeaderImpl(location == $loc)

then

    $result.addPassedRule("leader in homeland");

    update($result);

end

rule "abdication allowed"

when

    $result : RuleResult (rulesPassed not contains "abdication allowed"

            && rulesPassed contains "leaders in same location"

            && rulesPassed contains "leaders king and heir")

then

    $result.addPassedRule("abdication allowed");

    update($result);

end

________________________________

From: rules-users-bounces at lists.jboss.org [mailto:
rules-users-bounces at lists.jboss.org
<mailto:rules-users-bounces at lists.jboss.org> ] On Behalf Of Edson
Tirelli
Sent: Tuesday, October 30, 2007 2:31 PM
To: Rules Users List
Subject: Re: [rules-users] RE:
JavaConsequenceBuilder.buildNullPointerException

   Michael,

   Can you show us your rule(s) please? it is raising the NPE when
trying to get the list of variables you use in the consequence... as
soon as we determine what the real problem is, I can fix the error
message... 

   []s
   Edson

2007/10/30, Michael Fuller <mfuller at ihets.org>:

I have the following code: (note String[] ruleFiles contains only one
string)

public class Engine {

    private static RuleBase ruleBase;

    public void start(String[] ruleFiles) throws Exception {

        PackageBuilderConfiguration cfg = new
PackageBuilderConfiguration();

        JavaDialectConfiguration javaConf = (JavaDialectConfiguration)
cfg.getDialectConfiguration("java");

        javaConf.setCompiler(JavaDialectConfiguration.ECLIPSE);

        PackageBuilder builder = new PackageBuilder(cfg);

        for (String file : ruleFiles) {

            builder.addPackageFromDrl(new
InputStreamReader(ClassLoader.getSystemResourceAsStream(file)));

        }

        Package pkg = builder.getPackage();

        PackageBuilderErrors errors = builder.getErrors();

        if (errors.getErrors().length != 0) {

            // do something

        }

        RuleBaseConfiguration conf = new RuleBaseConfiguration();

conf.setAssertBehaviour(RuleBaseConfiguration.AssertBehaviour.EQUALITY);

        ruleBase = RuleBaseFactory.newRuleBase();

        ruleBase.addPackage(pkg);

        ruleBase.newStatefulSession(false);

    }

}

At the builder.addPackageFromDrl(new
InputStreamReader(ClassLoader.getSystemResourceAsStream(file))); line
I'm getting the following exception:

java.lang.NullPointerException

            at
org.drools.rule.builder.dialect.java.JavaConsequenceBuilder.build(JavaCo
nsequenceBuilder.java:54)

            at
org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:67)

            at
org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:446)

            at
org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:304)

            at
org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java
:167)

            at
myPackage.rivoli.service.rules.Engine.start(Engine.java:33)

            at
myPackage.rivoli.rules.LeaderKingAndHeirTest.setUp(LeaderKingAndHeirTest
.java:26)

            at
com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:40)

            at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)

            at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.jav
a:39)

            at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
Impl.java:25)

            at
com.intellij.rt.execution.application.AppMain.main(AppMain.java:90)

I am using Drools 4.0.3

I have the following jars in my class path:

antlr-runtime-3.0.jar 

core-3.2.3.v_686_R32x.jar

drools-compiler-4.0.3.jar

drools-core-4.0.3.jar

mvel14-1.2.10.jar

Any ideas would be helpful. Thanks.

Michael Fuller

"In theory there is no difference between theory and practice. But, in
practice, there is." - Jan L.A. van de Snepscheut

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-- 
  Edson Tirelli
  Software Engineer - JBoss Rules Core Developer
  Office: +55 11 3529-6000
  Mobile: +55 11 9287-5646 
  JBoss, a division of Red Hat @ www.jboss.com 

_______________________________________________
rules-users mailing list
rules-users at lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users

-- 
  Edson Tirelli
  Software Engineer - JBoss Rules Core Developer
  Office: +55 11 3529-6000
  Mobile: +55 11 9287-5646 
  JBoss, a division of Red Hat @ www.jboss.com 

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