package poxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
* Simple Dynamic Proxy, show a single interface - a single instance case.
*    
* @author daniel zhou
*/
public class SimpleDynamicProxy {
  /**
    * @param args
    */
  public static void main(String[] args) {
    //generate a hanlder
    ProxyHanlder hanlder=new ProxyHanlder();
    /*
     * register instance to hanlder, get the interface's proxy
     */
    Dog dogProxy=(Dog) hanlder.generateProxyHanlder(new Dog(){
      @Override
      public String eat(String food) {
        return "Daniel's dog just ate an "+ food +"!";
      }
    });
    //do method by proxy
    String result = dogProxy.eat("big bone");
    //take a look
    System.out.println(result);
  }
}

//Proxy Handler    
class ProxyHanlder implements InvocationHandler{
  //container
  Object obj = new Object();
    
  public Object generateProxyHanlder(Object obj) {
    //store it
    this.obj = obj;    
    //return interface proxy
    return Proxy.newProxyInstance(obj.getClass().getClassLoader(),
                     obj.getClass().getInterfaces(),
                     this);
  }

  @Override
  public Object invoke(Object proxy, Method method, Object[] args)
      throws Throwable {
    Object result=null;
    result=method.invoke(obj, args);
    return result;
  }
    
}

//interface
interface Dog{    
  String eat(String food);
}