java中对于混型的方案

所谓的混型就是让多个类的特性集中到一个类的上面,在java中主要有两种方案来针对这个问题,第一个是用接口,第二种使用动态代理的方式,如果使用第一种方式而且构造的对象模型非常复杂的话,那么对象的层次结构也将变的复杂,第二种方式显的更有灵活性,下面是两种方案的代码

package com.eric.generic;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.util.Date;import java.util.HashMap;import java.util.Map;public class MixinSolution {public static void main(String[] args) {/* * use interface to produce effect of mixing, to make EleWatch have * Watch,Clock Calendar functions */EleWatch ew = new EleWatch();ew.calendar();ew.clock();ew.printTime();/* * use dynamic proxy to produce effect of mixing */Object mixing = MixinHandler.newInstance(new Tuple2(new ClockImp(), Clock.class), new Tuple2(new CalendarImp(), Calendar.class));Clock clock = (Clock) mixing;clock.clock();Calendar calendar = (Calendar) mixing;calendar.calendar();}}// ............................................dynamic proxyclass MixinHandler implements InvocationHandler {private static Map<String, Object>delegateMethod= new HashMap<String, Object>();private MixinHandler(Tuple2<Object, Class<?>>... paris) {}private static void initDelegateMethods(Tuple2<Object, Class<?>>... paris) {for (Tuple2<Object, Class<?>> tuple2 : paris) {for (Method method : tuple2.b.getMethods()) {String methodName = method.getName();if (!delegateMethod.containsKey(methodName)) {// put method name as key, Object as value in deledateMethod// mapdelegateMethod.put(methodName, tuple2.a);}}}}public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {System.out.println("before invoke");String methodName = method.getName();Object delegate = delegateMethod.get(methodName);if (delegate != null) {return method.invoke(delegate, args);} else {throw new RuntimeException("method not found!");}}public static Object newInstance(Tuple2<Object, Class<?>>... pairs) {initDelegateMethods(pairs);Class<?>[] interfaces = new Class [pairs.length];int count = 0;for (Tuple2<Object, Class<?>> tuple2 : pairs) {interfaces[count++] = tuple2.b;}return Proxy.newProxyInstance(interfaces[0].getClassLoader(), interfaces, new MixinHandler());}}// ............................................interfaceinterface Clock {public void clock();}class ClockImp implements Clock {public void clock() {System.out.println("Clocking....");}}interface Calendar {public void calendar();}class CalendarImp implements Calendar {public void calendar() {System.out.println("Calending....");}}interface Timer {public void printTime();}class Watch implements Timer {public void printTime() {System.out.println(new Date());}}/* * use interface to produce effect of mixing, to make EleWatch have Watch,Clock * Calendar functions */class EleWatch extends Watch implements Clock, Calendar {private Clock clock     = new ClockImp();private Calendarcalendar= new CalendarImp();public void calendar() {calendar.calendar();}public void clock() {clock.clock();}}