/*
　　* Register a listener for a given interface. If the caller has not
　　 * been registered, then an error will be thrown.
　　*/
　　public void registerListener(Class iFace, Object o) {
　　CallBackHanlder handler;
　　if(!iFace.isAssignableFrom(o.getClass())){
　　throw new IllegalArgumentException("Object [" + o + "] does not " +
　　"implement [" + iFace.getName() +
　　"]");
　　}
　　synchronized (_iface2Handler) {
　　handler = (CallBackHanlder) _iface2Handler.get(iFace);
　　}
　　if(handler == null){
　　throw new IllegalArgumentException("No callback for interface [" +
　　iFace.getName() + "] exists");
　　}
　　handler.addListener(o);
　　}
　　/**
　　* @param args
　　*/
　　public static void main(String[] args) {
　　//Base testhandler
　　IndustrialDynamicProxy x=new IndustrialDynamicProxy();
　　//register iface, get the proxy
　　MyInterface caller = (MyInterface)x.generateCaller(MyInterface.class, CallBackType.RETURN_LAST);
　　//register the listener(real instance)
　　x.registerListener(MyInterface.class, new MyInterface(){
　　@Override
　　public int addTwo(int a, int b) {
　　System.out.println("Target method called");
　　return a + b;
　　}
　　});
　　//call the listener
　　int result=caller.addTwo(2, 4);
　　//take a look
　　System.out.println("addTwo(2,4):"+result);
　　}
　　/**
　　* An inner class to operate listeners in private
　　*/
　　static class CallBackHanlder implements InvocationHandler{
　　/*
　　* container of listeners (real instance)
　　* Note: work in multithread env
　　*/
　　private Set _listeners = new HashSet();
　　//tool of get right Type
　　private CallBackType _type = null;
　　CallBackHanlder(CallBackType type){
　　this._type=type;
　　}