simpleinvocationhandler.java

一个简单的java邮件系统源码

package com.easyjf.web.interceptor;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
/**
 * 简单的代理方法调用处理器
 * @author 大峡
 *
 */
public class SimpleInvocationHandler implements InvocationHandler {
	private Object target;
	private BeforeInterceptor[] beforeAdvices;
	private AfterInterceptor[] afterAdvices;
	private AroundInterceptor[] aroundAdvices;
	public SimpleInvocationHandler(Object target,Interceptor[] advices)
	{
		this.target=target;
		initAdvices(advices);
	}
	private void initAdvices(Interceptor[] advices)
	{
		if(advices!=null)
		{			
			java.util.List beforeList=new java.util.ArrayList();
			java.util.List afterList=new java.util.ArrayList();
			java.util.List aroundList=new java.util.ArrayList();
			for(int i=0;i<advices.length;i++)
			{
				if(advices[i] instanceof BeforeInterceptor)
				{
					beforeList.add(advices[i]);
				}
				else if(advices[i] instanceof AfterInterceptor)
				{
					afterList.add(advices[i]);
				}
				else if(advices[i] instanceof AroundInterceptor)
				{
					aroundList.add(advices[i]);
				}
			}
			if(beforeList.size()>0)
			{
				beforeAdvices=new BeforeInterceptor[beforeList.size()];
				for(int i=0;i<beforeList.size();i++)beforeAdvices[i]=(BeforeInterceptor)beforeList.get(i);				
			}
			if(afterList.size()>0)
			{
				afterAdvices=new AfterInterceptor[afterList.size()];
				for(int i=0;i<afterList.size();i++)afterAdvices[i]=(AfterInterceptor)afterList.get(i);				
			}
			if(aroundList.size()>0)
			{
				aroundAdvices=new AroundInterceptor[aroundList.size()];
				for(int i=0;i<aroundList.size();i++)aroundAdvices[i]=(AroundInterceptor)aroundList.get(i);				
			}			
		}
	}
	public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
		//处理方法前通知	
		Object ret=null;
		boolean haveAround=false;
		if(beforeAdvices!=null)
		{
			for(int i=0;i<beforeAdvices.length;i++)
			{
				BeforeInterceptor advice=beforeAdvices[i];
				advice.before(target,method, args);
			}
		}
		if(aroundAdvices!=null)
		{
			for(int i=0;i<aroundAdvices.length;i++)
			{
				haveAround=true;
				AroundInterceptor advice=aroundAdvices[i];
				ret=advice.invoke(new SimpleMethodInvocation(target,method,args));
			}
		}	
		if(!haveAround)	ret=method.invoke(target, args);	
		if(afterAdvices!=null)
		{
			for(int i=0;i<afterAdvices.length;i++)
			{
				afterAdvices[i].after(ret, target, method, args);			
			}
		}
		return ret;
	}
}