3:29 a.m.
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(a)lists.jboss.org [rules-users-bounces(a)lists.jboss.org] On Behalf
Of Swindells, Thomas [TSwindells(a)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(a)lists.jboss.org [mailto:rules-users-
bounces(a)lists.jboss.org] On Behalf Of Abhay B. Chaware
Sent: 09 June 2011 08:06
To: rules-users(a)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)
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