在读gigix的G－roller的时候，用到了proxy模式来实现给业务增加事务处理。其实在java的sdk中很多的设计模式都直接实现了，observer也是其中之一。但是因为这类api很少用到，也没机会去学习。而例子是最好的老师。
package com.bonjovi.test;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;
import java.lang.reflect.Method;
import java.util.Vector;
import java.util.List;
public class VectorProxy implements InvocationHandler {
private Object proxyobj;
/** @link dependency */
/* #Proxy lnkProxy; */
public VectorProxy(Object obj) {
proxyobj = obj;
}
public static Object factory(Object obj) {
Class cls = obj.getClass();
return Proxy.newProxyInstance(cls.getClassLoader(),
cls.getInterfaces(), new VectorProxy(obj));
}
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
System.out.println("before calling " + method);
if (args != null) {
for (int i = 0; i < args.length; i++) {
System.out.println(args[i] + "");
}
}
Object o = method.invoke(proxyobj, args);
System.out.println("after calling " + method);
return o;
}
public static void main(String[] args) {
List v = null;
v = (List) factory(new Vector(10));
v.add("New");
v.add("York");
}
}