The business representative model

The business representative model

The Business Delegate Pattern is used to decouple the representation and business layers. I t is basically used to reduce the ibility of communication or remote querying of business layer code in the representing layer code. We have the following entities in the business tier.

• Client - Indicates that the layer code can be JSP, servlet, or UI java code.
• Business Delegate - An entry class for client entities that provides access to business service methods.
• LookUp Service - Finding a service object is responsible for obtaining the relevant business implementation and providing access to the business object to the business representative object.
• Business Services - Business Services Interface. The entity class of the business service is implemented, providing the actual business implementation logic.

Realize

We'll create Client, BusinessDelegate, BusinessService, LookUpService, JMSService, and EJBService to represent the various entities in the business representative model.

BusinessDelegate PotternDemo, our demo class uses BusinessDelegate and Client to demonstrate the use of business representation patterns.

Step 1

Create a BusinessService interface.

BusinessService.java

public interface BusinessService {
   public void doProcessing();
}

Step 2

Create an entity service class.

EJBService.java

public class EJBService implements BusinessService {

   @Override
   public void doProcessing() {
      System.out.println("Processing task by invoking EJB Service");
   }
}

JMSService.java

public class JMSService implements BusinessService {

   @Override
   public void doProcessing() {
      System.out.println("Processing task by invoking JMS Service");
   }
}

Step 3

Create a business query service.

BusinessLookUp.java

public class BusinessLookUp {
   public BusinessService getBusinessService(String serviceType){
      if(serviceType.equalsIgnoreCase("EJB")){
         return new EJBService();
      }else {
         return new JMSService();
      }
   }
}

Step 4

Create a business representative.

BusinessDelegate.java

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();      
   }
}

Step 5

Create a client.

Client.java

public class Client {
   
   BusinessDelegate businessService;

   public Client(BusinessDelegate businessService){
      this.businessService  = businessService;
   }

   public void doTask(){     
      businessService.doTask();
   }
}

Step 6

Use the BusinessDelegate and Client classes to demonstrate the business representative model.

BusinessDelegatePatternDemo.java

public class BusinessDelegatePatternDemo {
   
   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();
   }
}

Step 7

Verify the output.

Processing task by invoking EJB Service
Processing task by invoking JMS Service