[rules-users] couuld not load fact to rule engine

[Ilya Sterin]

You have to inject the same class loader which loaded your dynamic
class into the drools.  Here is the blog post outlining how to do it
as well as some caveats with classloaders...

http://www.ilyasterin.com/blog/2009/10/java-multiple-class-loaders-issue.html

On Tue, Oct 27, 2009 at 2:30 AM, Hemanth kumar <hemanth at saha.in> wrote:
>
>
> hi,
> Im working on a sample test project.
> In that im dynamically creating a class ( fact) and compiling it.
>
> here is my test project
> --------------------------------------------------------------------------------------
> mainJavaclass
>
>
> public void runRule()
>         {
>                 try {
>                            System.out.println("\nRunning rule\n");
>
>                                // go !
>
>                                URL[] urls = new URL[]{ new URL("file://"+path) };
>
>                                URLClassLoader ucl =  new URLClassLoader(urls);
>                                Class<?> clazz  = ucl.loadClass("test.Message");
>                                Object classObj = clazz.newInstance();
>
>
>                                Method method = clazz.getDeclaredMethod("setMessage", new
> Class[]{String.class});
>
>                                //System.out.println("facts loaded\n");
>
>                                method.invoke(classObj, new Object[]{"Hello"});
>
>
>                                log.info("==== Calling Rule Runner ======");
>
>                                Collection facts = new ArrayList();
>                                facts.add(classObj);
>
>
>                                // Load and fire our rules files against the data
>                                new RuleRunner().runStatelessRules(RULES_FILES, null, facts, null, null,
> logger);
>
>                        }
>                        catch (Throwable t) {
>                                t.printStackTrace();
>                        }
>
>         }
>
> ----------------------------------------------------------------------
> Fact
>
> package test;
> public class Message{
> private String message;
> public String getMessage(){
> return this.message;
> }
>
> public void setMessage(String message) {
> this.message = message;
> }
>
> }
>
>
> ------------------------------------------------------------------------
> sample rule
>
> package test
> import test.Message;
>
> rule "Your First Rule"
>     dialect "mvel"
>     when
>          m:Message(message != "Good Bye"  )
>     then
>          System.out.println("First Rule fired    "+m.message );
>          modify(m){ message = "Good Bye"};
> end
> -----------------------------------------------------------------
> console file  http://www.nabble.com/file/p26072723/console.PNG console.PNG
>
> what happens is when i was running the project inside eclipse IDE it works
> fine but when i hosted in tomcat and calling from outside ide the rule is
> not getting fired.
> I think the dyanamically loaded class is not recognised by the rule engine.
>
> suggest me any ideas
>
> Hemanth
> --
> View this message in context: http://www.nabble.com/couuld-not-load-fact-to-rule-engine-tp26072723p26072723.html
> Sent from the drools - user mailing list archive at Nabble.com.
>
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