[rules-users] Class loader problem

[Ilya Sterin]

Hemanth, I had a similar issue, here is a blog post...

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

Hope this helps.

On Tue, Nov 3, 2009 at 5:27 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
> -----------------------------------------------------------------
> http://old.nabble.com/file/p26160051/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 or post an working example
>
> Hemanth
> --
> View this message in context: http://old.nabble.com/Class-loader-problem-tp26160051p26160051.html
> Sent from the drools - user mailing list archive at Nabble.com.
>
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