职责链模式

来源：互联网发布：网络大电影制作编辑：程序博客网时间：2024/06/05 10:02

职责链模式：使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系。将这个对象连成一条链，并沿着这条链传递该请求，指导有一个对象处理为止。

当客户提交一个请求时，请求沿着链传递直至有一个ConcreteHandler对象负责处理它。

    class Program    {        static void Main(string[] args)        {            Handler h1 = new ConcreteHandler1();            Handler h2 = new ConcreteHandler2();            Handler h3 = new ConcreteHandler3();            h1.SetSuccessor(h2);            h2.SetSuccessor(h3);            int[] requests = { 2, 5, 14, 22, 18, 3, 27, 20 };            foreach (int request in requests)            {                h1.HandleRequest(request);            }            Console.Read();        }    }    abstract class Handler    {        protected Handler successor;        public void SetSuccessor(Handler successor)        {            this.successor = successor;        }        public abstract void HandleRequest(int request);    }    class ConcreteHandler1 : Handler    {        public override void HandleRequest(int request)        {            if (request >= 0 && request < 10)            {                Console.WriteLine("{0}  处理请求  {1}",                  this.GetType().Name, request);            }            else if (successor != null)            {                successor.HandleRequest(request);            }        }    }    class ConcreteHandler2 : Handler    {        public override void HandleRequest(int request)        {            if (request >= 10 && request < 20)            {                Console.WriteLine("{0}  处理请求  {1}",                  this.GetType().Name, request);            }            else if (successor != null)            {                successor.HandleRequest(request);            }        }    }    class ConcreteHandler3 : Handler    {        public override void HandleRequest(int request)        {            if (request >= 20 && request < 30)            {                Console.WriteLine("{0}  处理请求  {1}",                  this.GetType().Name, request);            }            else if (successor != null)            {                successor.HandleRequest(request);            }        }    }

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