职责链 评价：挺好玩的 稍微复杂版 类似出栈入栈 （原理职责链调用一个之后跳转到第二个执行在跳转第三个执行 接下来因为每次调用完后都会返回被调用的位置）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication20
{
    public class Response
    {
        public string ResponseStr { get; set; }
         
        
    }

    public class Request
    {
        public string RequestStr { get; set; }
    }

    public interface IFiler
    {
        void doFilter(Request requestStr,Response str,FilterChain fc);
    }

    public class AFilter:IFiler
    {
        public void doFilter(Request request,Response response,FilterChain fc)
        {
            request.RequestStr = request.RequestStr + "--->AFilter";
            fc.SetFilter(request,response,fc);
            response.ResponseStr = response.ResponseStr + "--->AFilter";
        }
    }

    public class BFilter : IFiler
    {
        public void doFilter(Request request, Response response,FilterChain fc)
        {
            request.RequestStr = request.RequestStr + "--->BFilter";
            fc.SetFilter(request,response,fc);
            response.ResponseStr = response.ResponseStr + "--->BFilter";
        }
    }

    public class CFilter : IFiler
    {
        public void doFilter(Request request, Response response,FilterChain fc)
        {
            request.RequestStr = request.RequestStr + "--->CFilter";
            fc.SetFilter(request, response, fc);
            response.ResponseStr = response.ResponseStr + "--->CFilter";
        }
    }
    public class FilterChain
    {
        IList<IFiler> fcFilers = new List<IFiler>();
        private int index = 0;
        public FilterChain AddFilter(IFiler f)
        {
            fcFilers.Add(f);
            return this;
        }

        public void SetFilter(Request request,Response response,FilterChain fc)
        {
            if (index == fcFilers.Count) return;
            IFiler f = fcFilers[index];
            index++;
            f.doFilter(request,response,fc);
        }

    }
    class Program
    {
        static void Main(string[] args)
        {
            //客户端处理敏感信息

            Response respons=new Response();
            Request request=new Request();
            respons.ResponseStr = "response";
            request.RequestStr = "request";
            FilterChain fc=new FilterChain();
            fc.AddFilter(new AFilter()).AddFilter(new BFilter()).AddFilter(new CFilter());
            fc.SetFilter(request,respons,fc);
            Console.WriteLine(request.RequestStr+" "+respons.ResponseStr);
            Console.ReadKey();


        }
    }


}