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

Maxim Veksler maxim.veksler at gmail.com
Mon Nov 17 12:17:24 EST 2008


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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