Bean Introspection

Question

A class containing some methods and EventListeners.By introspection I want to get only the methods and EventListeners.
But MethodDescriptor is returning all the things while EventSetDescriptor returning nun of these.
How to get name of the EventListener ???
//this is the Bean Class
public interface MySampleResource
extends Resource
// Properties
// =============================================================================================
* Return the value of the PropertyX property, which has an integer value.
* This is a read only property and has one to one relationship with a
* field.
* <p>
* Although the resource exposes a normal getter, the application programmer
* has to keep in mind, that the property value might be unavailable in a
* distributed environment (for various reasons) and that the
* ResourceExceptions thrown have to be handled in the proper way.
* @throws ResourceException - if the value is not immediately available.
public int getPropertyX ()
throws ResourceException;
* Return the value of PropertyY. This is a read/write property and has one
* to one relationship with a field.
public int getPropertyY ()
throws ResourceException;
* TODO SAUK: add a function abstract.
public int getPropertyZ ()
throws ResourceException;
// public int setPropertyZ (int x)
// throws ResourceException;
* Set the value of PropertyY property.
* <p>
* Setting a property value (like other method calls also) in a distributed
* environment is only possible in the backend end (provider side), i.e. the
* setter has to be relayed to that end.
* <p>
* Since during that remote invocation things can go wrong with the call
* itself (not the backend function as such) the setter might throw related
* ResourceExceptions.
public void setPropertyY (int aValue)
throws ResourceException;
// Method calls
// =============================================================================================
* TODO SAUK: add a function abstract.
public void functionX (int anIntArgument)
throws ResourceException;
* TODO SAUK: add a function abstract.
public String functionY (String aStringArgument)
throws ResourceException;
* TODO SAUK: add a function abstract.
public void functionZ (int anIntArgument, String aStringArgument)
throws ResourceException;
// Event Generation Infrastructure
// =============================================================================================
* Add aListener to the list of all listeners for this resource.
public void addMySampleResourceListener (MySampleResourceListener aListener);
* Remove aListener from the list of listeners of this resource.
public void removeMySampleResourceListener (MySampleResourceListener aListener);
//while I am attempting the following code
BeanInfo beanInfo = Introspector.getBeanInfo(c);
EventSetDescriptor[] eventSetDescriptor = beanInfo.getEventSetDescriptors();
for (int i = 0; i < eventSetDescriptor.length; i++)
System.out.println("Event Name: " + eventSetDescriptor.getName());
//why it is not working ????

Answer 1

Okay, that would be your problem.
Your interface MySampleResourceListener MUST extend EventListener or some other subinterface of EventListener, or the Introspector will simply ignore it. You can check this yourself. The method of the introspector that checks this is called getTargetEventInfo. You should be able to find it in the source for the introspector.
It contains an if structure on the line isSubclass(listener, EventListenerType), where listener is the type of listener it's inspecting (i.e. the MySampleResourceListener), EventListenerType is EventListener.class, and isSubclass is a routine to check if listener is a subclass (or subInterface) of EventListenerType.
The solution is this: simply extend EventListener.
From Java API: (EventListener is) A tagging interface that all EventListeners MUST extend.
Give that a try, and see if it works for you. Good Luck!