27) Business Delegate Pattern

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();
    }
}

interface BusinessService {
    public void doProcessing();
}

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

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

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

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();
    }
}

class Client {
    BusinessDelegate businessService;

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

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

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