设计模式学习—业务代表模式(Business Delegate Design Pattern)

柔情只为你懂 2022-06-09 11:51 121阅读 0赞

# 一、我的理解 #

该模式主要是将业务实现和前端展示分割，由一个中间代表来连接客户端和业务端，减少客户端和业务端的通信复杂度。

# 二、实现方式 #

业务实现向外统一暴露接口，由业务代表来具体查询和掉用业务接口执行相关业务，而客户则只需要想业务代表调用相关简化后的接口即可实现响应业务。

# 三、实例 #

![Center][]

###### Java实例 ######

BusinessService接口：业务实现统一向外暴露的接口

package com.study.dp.business.delegate;
    
    public interface BusinessService {
    
        public void doProcessing();
        
    }

EJBService类：业务的实际实现方式一

package com.study.dp.business.delegate;
    
    public class EJBService implements BusinessService {
    
        @Override
        public void doProcessing() {
            System.out.println("Processing task by invoking EJB Service");
        }
    
    }

JMSService类：业务的实际实现方式二

package com.study.dp.business.delegate;
    
    public class JMSService implements BusinessService {
    
        @Override
        public void doProcessing() {
            System.out.println("Processing task by invoking JMS Service");
        }
    
    }

BusinessLookUp类：业务查询类，有点类似于业务实现的工厂模式

package com.study.dp.business.delegate;
    
    public class BusinessLookUp {
    
        public BusinessService getBusinessService(String serviceType) {
            if(serviceType.equalsIgnoreCase("EJB")) {
                return new EJBService();
            }else {
                return new JMSService();
            }
        }
        
    }

BusinessDelegate类：业务代表类，向客户端提供调用接口

package com.study.dp.business.delegate;
    
    public class BusinessDelegate {
    
        private BusinessLookUp lookupService = new BusinessLookUp();
        private BusinessService businessService;
        private String serviceType;
        
        public void setServiceType(String serviceType) {
            this.serviceType = serviceType;
        }
       
        public void doTask() {
            businessService = lookupService.getBusinessService(serviceType);
            businessService.doProcessing();
        }
    }

Client类：客户端

package com.study.dp.business.delegate;
    
    public class Client {
    
        BusinessDelegate businessService;
        
        public Client(BusinessDelegate businessService) {
            this.businessService = businessService;
        }
        
        public void doTask() {
            businessService.doTask();
        }
        
    }

Demo类：测试类

package com.study.dp.business.delegate;
    
    public class Demo {
    
        public static void main(String[] args) {
            BusinessDelegate businessDelegate = new BusinessDelegate();
            businessDelegate.setServiceType("EJB");
            
            Client client = new Client(businessDelegate);
            client.doTask();
            
            businessDelegate.setServiceType("JMS");
            client.doTask();
        }
        
    }

# 四、应用场景 #

[Center]: /images/20220609/5faff2f26633495c87f434b3d12ef206.png