[rules-users] Problem : Run Drool Application From Command Prompt

[nesta.fdb]

I think that you need to put java compiler to your classpath.
try eclipse's core-3.4.2.v_883_R34x.jar.




在2009-07-21，Pankaj.Jain at lntinfotech.com 写道：

Hi

I am trying to integrate Drool with ofbiz and run application from command prompt. In one way I have integrated it properly and I am able to run it successfully.

Code : Which I was using initially

KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); 

or

PackageBuilderConfiguration cfg = new PackageBuilderConfiguration();
KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); 

Exception I got :

org.drools.RuntimeDroolsException: Unable to load dialect 'org.drools.rule.builder.dialect.java.JavaDialectConfiguration:java 
:org.drools.rule.builder.dialect.java.JavaDialectConfiguration'
at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:274) at org.drools.compiler.PackageBuilderConfiguration.buildDialectConfigurationMap(PackageBuilderConfiguration.java:259) 

at org.drools.compiler.PackageBuilderConfiguration.init(PackageBuilderConfiguration.java:176) at org.drools.compiler.PackageBuilderConfiguration.<init>(PackageBuilderConfiguration.java:153) at org.drools.compiler.PackageBuilder.<init>(PackageBuilder.java:242) 
.
.
.
Caused by: java.lang.NullPointerException
at org.drools.rule.builder.dialect.java.JavaDialectConfiguration.setCompiler(JavaDialectConfiguration.java:92) at org.drools.rule.builder.dialect.java.JavaDialectConfiguration.init(JavaDialectConfiguration.java:55) at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:270

Problem I found : 
In the class JavaDialectConfiguration in jar file drools-compiler.jar there is a method named "setCompliler",  in this method Null Pointer Exception was coming.

Solution I provided :
In my application I created my custom class CustomJavaDialectConfiguration by extending to class JavaDialectConfiguration, In this class I overrided the method setCompiler. My method was exactly same as that of method setCompiler in JavaDialectConfiguration . To call my dialect class I also overrided the method "addDialect" of PackageBuilderConfiguration class . For that I created class CustomPackageBuilderConfiguration by extending to PackageBuilderConfiguration. 
after that I wrote the code:

PackageBuilderConfiguration cfg = new CustomPackageBuilderConfiguration();
KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(cfg);


Now application is running perfectly fine from both eclipse and command prompt without any exception.

I want to know as my overrided method "setCompiler" was exactly same then why I had to override method, and In original code (ie in drools-compiler.jar file) why it was giving exception  ???  Was that due to class lader or something else ??  Please do help in this regard ....

Thanks & Regards:

Pankaj Jain | L&T infotech |Navi Mumbai
Mobile: +91 9920218945
Email : pankaj.jain at lntinfotech.com
www.Lntinfotech.com

"Whatever the mind of man can conceive & believe, it can achieve."

Larsen & Toubro Infotech Ltd.
www.Lntinfotech.com

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