[rules-users] Class loader problem

[Hemanth Yerra]

swapnil thanx for the reply,
this is my modified code

try{

            System.out.println("Initializing Fact....");

            URL[] urls = new URL[]{ new URL("file://"+path) };
             ClassLoader loader =  new URLClassLoader(urls);
             Class clazz  = loader.loadClass("test.Message");
                              //Class.forName("test.Message", false, ucl);
             Object factObj = clazz.newInstance();
             String ruleFile = "test/Sample.drl";

             Method method = clazz.getMethod("setMessage", new
Class[]{String.class});
             Method method1 = clazz.getMethod("getMessage");
             //System.out.println("facts loaded\n");

             method.invoke(factObj, new Object[]{"Hello"});

             System.out.println("initializing packageBuilder");

             PackageBuilderConfiguration config = new
PackageBuilderConfiguration();
             config.setClassLoader(loader);

            KnowledgeBuilder kbuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder(config);

            System.out.println("finding Rule");

kbuilder.add(ResourceFactory.newClassPathResource("test/Sample.drl"),ResourceType.DRL);

            if (kbuilder.hasErrors())
                  throw new RuntimeException("Unable to compile rules. " +
                            kbuilder.getErrors().toString());


            KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(new
RuleBaseConfiguration(loader));

            kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());

            StatelessKnowledgeSession session =
kbase.newStatelessKnowledgeSession();

            System.out.println("running rule....... \n");
             session.execute(factObj);

             System.out.println("\nend...\n");
             System.out.println(method1.invoke(factObj).toString());
        }
        catch (Throwable t) {
            t.printStackTrace();
        }

thanx and regards
Hemanth



2009/11/3 Swapnil Raverkar <swapnil.raverkar at gmail.com>

> Are you inserting the instance of the dynamically loaded class into the
> KnowledgeBase?
> i.e. session.insert(dynamicInstance);
>
> If not the rule won't get fired.
>
>
> Cheers,
>
> Swapnil
>
> 2009/11/3 Hemanth kumar <hemanth at saha.in>
>
>
>> 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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>>
>
>
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-- 
regards
Hemanth kumar
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