[rules-users] (interesting) migration problem from Drools 3.0.6 toDrools 4.0.7

[Joe White]

Maxim,

Are the classes you are trying to reference multiple levels of inner classes? Drools 4 cannot reference nested inner classes in drl. That issue is fixed in the release for drools 5.

 

Joe

 

From: rules-users-bounces at lists.jboss.org [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Maxim Veksler
Sent: Monday, November 17, 2008 10:17 AM
To: Rules Users List
Subject: [rules-users] (interesting) migration problem from Drools 3.0.6 toDrools 4.0.7

 

Hello Everyone,

Here's a fun stuff to debug:


In our application we are using the concept of "Dynamic Beans", Drools is running in a webapp. The servlet container is tomcat6.

Dynamic beans are beans we compile from java code and then load with a custom class loader. This happens in the following method :

The class that implements ServletContextListener has in his contextInitialized(...) method a code to do the following: (simplification)

ClassLoader cl = Janino.JavaSourceClassLoader(...)
originalCl = Thread.currentThread().getContextClassLoader();
Thread.currentThread().setContextClassLoader(cl);

The above code allowed drools3 to find the Dynamic Classes (which didn't even existed, not to be mention were available to ANY classloader).


Now, inside the .drl files we use properties from these dynamic beans - This allows us to be dynamic on the properties we can filter by.

All good, but now comes the new Drools4 code. The application is no longer able to find the mentioned classes. 
The only changes the I've done was change Drools version from 3 to 4. 

The errors I'm getting are of the form :

Rule Compilation error : [Rule name=X Status, agendaGroup=MAIN, salience=0, no-loop=false]
    com/X/ruleEngine/filtering/Rule_X_Status_0.java (2:267) : Only a type can be imported. com.X.common.dataModel.facts.dynamic.X resolves to a package
    com/X/ruleEngine/filtering/Rule_X_Status_0.java (2:334) : Only a type can be imported. com.X.common.dataModel.facts.dynamic.X resolves to a package
    com/X/ruleEngine/filtering/Rule_X_Status_0.java (2:1111) : Only a type can be imported. com.X.common.dataModel.facts.banner.X resolves to a package
    com/X/ruleEngine/filtering/Rule_X_Status_0.java (2:1379) : The import com.X.common.dataModel.facts.X.X cannot be resolved
...

Anyone has ideas how to over come this?

I'm currently searching for alternatives, I'm thinking about Configuring my custom class loader at the webapp level or something like that... 
Help would be appreciated as I'm not getting much success.

-- 
Cheers, 
Maxim Veksler

"Free as in Freedom" - Do u GNU ?

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