[rules-users] Drools in non-eclipse environment

Wolfgang Laun wolfgang.laun at gmail.com
Thu Jun 9 05:16:44 EDT 2011


You might try this:

     Properties props = new Properties();
     props.put( "drools.dialect.java.compiler", "JANINO" );

    KnowledgeBuilderConfiguration kbConfig =
        KnowledgeBuilderFactory.newKnowledgeBuilderConfiguration( props,
(ClassLoader[]) null );

Requires the janino jar in your classpath, which I have as
   ~/.m2/repository/janino/janino/2.5.15/janino-2.5.15.jar

-W

On 9 June 2011 10:29, Abhay B. Chaware <Abhay.Chaware at kpitcummins.com>wrote:

> I am using drools 5.1.0
>
> Let me explain what I am trying to do.  I am trying to write a drools app
> on to android platform.  In my app, I have added following jars in the
> application classpath -
>
> antlr-runtime.jar
> drools-api.jar
> drools-compiler.jar
> drools-core.jar
> mvel2.jar
>
> Do I need any other jar files ?
>
> upon drilling down into the Null Pointer Exception, it appears that it is
> throwing NPE at following line inside RuleBuilder.java
>
>
>    RuleConditionBuilder builder =
> (RuleConditionBuilder)context.getDialect().getBuilder(ruleDescr.getLhs().getClass());
>
> and on further drilling, I found that "context.getDialect()" is retuning
> NULL.
>
> Then I put some debug inside PackageBuilder.java
>
> upon drilling down for the error, found out that it is not able to set the
> context's dialect.
> ctr.getDialect(pkgRegistry.getDialect()) gives "null" ...
>
> DialectCompiletimeRegistry ctr =
> pkgRegistry.getDialectCompiletimeRegistry();
> RuleBuildContext context = new RuleBuildContext(this, ruleDescr, ctr, pkg,
> ctr.getDialect(pkgRegistry.getDialect()));
>
> Is there any default setting /configuration that I am obviously missing ?
>
> what could be the problem ?
>
> -abhay
>
>
> ________________________________________
> From: rules-users-bounces at lists.jboss.org [
> rules-users-bounces at lists.jboss.org] On Behalf Of Swindells, Thomas [
> TSwindells at nds.com]
> Sent: Thursday, June 09, 2011 1:40 PM
> To: Rules Users List
> Subject: Re: [rules-users] Drools in non-eclipse environment
>
> Which version of drools is this?
> For drools 5.0.1 we just use maven to resolve the dependencies for us and
> it works fine. I can't obviously see any eclipse compiler in the jars that
> we distribute with our application.
>
> Thomas
>
> > -----Original Message-----
> > From: rules-users-bounces at lists.jboss.org [mailto:rules-users-
> > bounces at lists.jboss.org] On Behalf Of Abhay B. Chaware
> > Sent: 09 June 2011 08:06
> > To: rules-users at lists.jboss.org
> > Subject: [rules-users] Drools in non-eclipse environment
> >
> > Has anyone tried using drools in non-eclipse env ? meaning that
> > org.eclipse.jdt.core_3.5.1.v_972_R35x.jar is not in the classpath ?
> >
> > Documentation says this :
> >
> > (http://docs.huihoo.com/drools/4.0.7/ch02s05.html)
> >
> > if you do not have Eclipse JDT Core in your classpath you must override
> the
> > compiler setting before you instantiate this PackageBuilder, you can
> either
> > do that with a packagebuilder properties file the ChainedProperties class
> will
> > find, or you can do it programmatically as shown below; note this time I
> use
> > properties to inject the value for startup.
> >
> > They also provide an example, but I am not able to figure out exactly how
> to
> > use this example/info.
> >
> > Here is my code :
> >
> >               KnowledgeBuilder kbuilder =
> > KnowledgeBuilderFactory.newKnowledgeBuilder();
> >               kbuilder.add(ResourceFactory.newInputStreamResource(is),
> > ResourceType.DRL);
> >
> > where "is" is input stream containing the rule file ( .drl)
> >
> > How do I override the compiler setting ?
> >
> > I am getting a null pointer exception ( see below ) and I suspect that
> > overriding the packagebuilderconfiguration will fix it ?
> >
> > W/System.err(25511): java.lang.NullPointerException
> > W/System.err(25511):    at
> > org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:47)
> > W/System.err(25511):    at
> > org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:1161)
> > W/System.err(25511):    at
> > org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:637)
> > W/System.err(25511):    at
> > org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java
> > :267)
> > W/System.err(25511):    at
> > org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder
> > .java:459)
> > W/System.err(25511):    at
> > org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.ja
> > va:28)
> > W/System.err(25511):    at
> > com.ts.DBconnector.readKnowledgeBase(DBconnector.java:146)
> >
> >
> >
> > _______________________________________________
> > rules-users mailing list
> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
>
>
>
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