业务代表模式(Business Delegate Pattern)用于对表示层和业务层解耦。它基本上是用来减少通信或对表示层代码中的业务层代码的远程查询功能。在业务层中我们有以下实体。
客户端(Client) - 表示层代码可以是 JSP、servlet 或 UI java 代码。
业务代表(Business Delegate) - 一个为客户端实体提供的入口类,它提供了对业务服务方法的访问。
查询服务(LookUp Service) - 查找服务对象负责获取相关的业务实现,并提供业务对象对业务代表对象的访问
业务服务(Business Service) - 业务服务接口。实现了该业务服务的实体类,提供了实际的业务实现逻辑。
代码:
1.业务接口
//业务
public interface BusinessService {
void doProcessing();
}
public class EJBService implements BusinessService{
@Override
public void doProcessing() {
System.out.println("invoking EJBService...");
}
}
public class JMSService implements BusinessService{
@Override
public void doProcessing() {
System.out.println("invoking JMSService...");
}
}
2.查询服务(LookUp Service)
public class BusinessLookUp {
public BusinessService getBusinessService(String type) {
if("EJB".equalsIgnoreCase(type)) {
return new EJBService();
}
return new JMSService();
}
}
3.业务代表
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();
}
}
4.客户端
public class Client {
BusinessDelegate delegate;
public Client(BusinessDelegate delegate) {
super();
this.delegate = delegate;
}
public void doTask() {
delegate.doTask();
}
}
5.测试
public class Test {
public static void main(String[] args) {
BusinessDelegate delegate=new BusinessDelegate();
delegate.setServiceType("EJB");
Client client=new Client(delegate);
client.doTask();
}
}
6.结果
invoking EJBService...
7.结论
表示层和业务层解耦了,减少了通信,提供了远程查询功能。
转载于
http://www.runoob.com/design-pattern/business-delegate-pattern.html