设计模式：责任链模式

r囧r小猫 2022-04-25 10:02 286阅读 0赞

书上定义：  
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受者之间的耦合关系。将这个对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为止。  
**好处**：

*  降低耦合度
 *  简化对象的相互连接
 *  加强给对象指派职责的灵活性
 *  增加新的请求处理类非常方便

**缺点：**

*  不能保证请求一定会被接受
 *  系统性能将会受到一定影响，而且在进行代码调试时会不太方便。
 *  可能会造成循环调用

定义个经理类抽象类：

public abstract class Manager {
    
        protected String name;
    
        protected Manager superior;
    
        public Manager(String name){
    
            this.name = name;
        }
    
        public void SetSuperior(Manager superior){
    
            this.superior = superior;
        }
    
        abstract public void RequestApplications(Request request);
    
    }

定义CommonManager经理类

package com.hnist.lzn.DesginModuel.DutyChaine;
    
    public class CommonManager extends Manager {
    
        public CommonManager(String name){
    
            super(name);
        }
    
        @Override
        public void RequestApplications(Request request) {
    
            if(request.RequestType == "请假" && request.Number <= 2)
            {
                System.out.println("经理批准请假");
    
            }else{
    
                if(superior!=null)
                    superior.RequestApplications(request);
            }
    
        }
    }

定义一个总监

package com.hnist.lzn.DesginModuel.DutyChaine;
    
    public class Majordomo extends Manager {
    
        public Majordomo(String name){
    
            super(name);
        }
    
        @Override
        public void RequestApplications(Request request) {
    
            if(request.RequestType == "请假" && request.Number <= 5)
            {
    
                System.out.println("总监批准请假");
            }else{
    
                if(superior!=null){
    
                    superior.RequestApplications(request);
                }
    
            }
    
        }
    }

定义一个总经理

package com.hnist.lzn.DesginModuel.DutyChaine;
    
    public class GeneralManager extends Manager {
    
    
        public GeneralManager(String name){
    
            super(name);
        }
    
        @Override
        public void RequestApplications(Request request) {
    
            if(request.RequestType == "请假")
            {
    
                System.out.println("总经理批准请假");
            }else if(request.RequestType == "加薪"&&request.Number <= 500){
    
                System.out.println("批准加薪");
            }else if(request.RequestType == "加薪" && request.Number > 500)
            {
                System.out.println("再说吧"
                );
    
            }
    
        }
    }

定义一个Request类

package com.hnist.lzn.DesginModuel.DutyChaine;
    
    public class Request {
    
        public int Number;
    
        public String RequestType;
    
        public Request(int number, String requestType){
            this.Number = number;
    
            this.RequestType = requestType;
    
        }
    
    }

测试：

package com.hnist.lzn.DesginModuel.DutyChaine;
    
    public class Main {
    
        public static void main(String[] args) {
    
            CommonManager commonManager = new CommonManager("经理");
    
            GeneralManager generalManager = new GeneralManager("总经理");
    
            Majordomo majordomo = new Majordomo("总监");
    
            commonManager.SetSuperior(majordomo);
            majordomo.SetSuperior(generalManager);
    
            Request request = new Request(600,"加薪");
    
            commonManager.RequestApplications(request);
    
        }
    
    }

结果：再说吧