职责链模式- Chain of Responsibility

Posted 2022-09-29

职责链模式(Chain of Responsibility): 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，并沿着这条链传递请求，直到有一个对象处理它为止。

职责链模式结构图：

代码实现

Handler类，定义一个处理请求的接口
 abstract class Handler
 
  protected Handler successor;
  //设置继任者
  public void SetSuccessor(Handler successor)
  
   this.successor = successor;
  
  public abstract void HandlerRequest(int request);
 
 ConcreHandler类，具体处理者类，处理它所负责的请求，可访问它的后继者，如果可处理该请求就处理，否则将该求转发给后继者
 class ConcreteHandler1 : Handler
 
  public override void HandlerRequest(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 ConcreteHandler1 : Handler
 
  public override void HandlerRequest(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); 
   
   
  
 ---客户端代码---
 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 = 2,5,14,22,8,5,20;
 foreach(int request in requests)
  
   h1.HandleRequest(request);
  
  Console.Read();