[jboss-dev-forums] [Design of POJO Server] - Re: JBAS-5578 ServiceMBeanSupport as MC bean

[adrian@jboss.org]

Never mind, I think I figured out what the problem is.

The issue occurs when you register a ServiceMBeanSupport MBean using registerDirect=true on the JMX annotation.

The callstack then goes something like:
MC - > ServiceMBeanSupport.create() -> ServiceController.create()
ServiceController.create() then ignores the request because it thinks it is a call
on the JMX lifecycle, i.e. a duplicate

I fixed this problem by introducing POJO lifecycle events in ServiceMBeanSupport
so we can differentiate the two.

  |    @Create
  |    public void pojoCreate() throws Exception
  |    {
  |       jbossInternalCreate();
  |    }
  | 

This brings up to other issues. The first of which I fixed which is related
to the confusion when JMX and POJO lifecycles.

If you invoke a lifecycle operation on the JMX console (or any MBeanServer operation)
then it should be redirected to the MC for a POJO not the ServiceController.
The JMX part is just a wrapper.
Since we now have the seperate pojoXXX methods, this is easy to spot,
so ServiceMBeanSupport now does the redirection, e.g.

  | public class ServiceMBeanSupport
  |    extends JBossNotificationBroadcasterSupport
  |    implements ServiceMBean, MBeanRegistration, 
  | 
  | // Implement this interface so we know the true name not the JMX wrapper
  | // when we are registered as a POJO
  | KernelControllerContextAware
  |    
  |    public void setKernelControllerContext(KernelControllerContext controllerContext) throws Exception
  |    {
  |       this.controllerContext = controllerContext;
  |    }
  | 
  |    public void unsetKernelControllerContext(KernelControllerContext controllerContext) throws Exception
  |    {
  |       this.controllerContext = null;
  |    }
  | 
  | // Redirect JMX invocations to the real MC context, e.g.
  |    
  |    public void create() throws Exception
  |    {
  |       if (controllerContext != null)
  |          pojoChange(ControllerState.CREATE);
  |       else if (serviceName != null && isJBossInternalLifecycleExposed)
  |          server.invoke(ServiceController.OBJECT_NAME, "create", new Object[] { serviceName }, SERVICE_CONTROLLER_SIG);
  |       else
  |          jbossInternalCreate();
  |    }
  | 

The second issue is the use of StandardMBean in the @JMX handling.
The problem is that this masks any implemention of MBeanRegistration
or NotificationEmitter.

This is probably not a real issue since you can always use
registerDirectly=true on the @JMX annotation
to expose those contracts.
You're pretty certain its going to be a real mbean if you implements them.

A more general fix would to use of an extension of StandardMBean
that delegates those interface implementations to underlying pojo
if it implements them.

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