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Business Delegate

StructuralDecouplingAbout 2 min


The Business Delegate pattern adds an abstraction layer between presentation and business tiers. By using the pattern we gain loose coupling between the tiers and encapsulate knowledge about how to locate, connect to, and interact with the business objects that make up the application.

Also known as

Service Representative


Real world example

A mobile phone application promises to stream any movie in existence to your device. It captures the user's search string and passes this on to the Business Delegate. The Business Delegate selects the most suitable video streaming service and plays the video from there.

In Plain Words

Business Delegate adds an abstraction layer between the presentation and business tiers.

Wikipedia says

Business Delegate is a Java EE design pattern. This pattern is directing to reduce the coupling in between business services and the connected presentation tier, and to hide the implementation details of services (including lookup and accessibility of EJB architecture). Business Delegates acts as an adaptor to invoke business objects from the presentation tier.

Programmatic Example

First, we have an abstraction for video streaming services and a couple of implementations.

public interface VideoStreamingService {
    void doProcessing();

public class NetflixService implements VideoStreamingService {
    public void doProcessing() {"NetflixService is now processing");

public class YouTubeService implements VideoStreamingService {
    public void doProcessing() {"YouTubeService is now processing");

Then, we have a lookup service that decides which video streaming service to use.

public class BusinessLookup {

    private NetflixService netflixService;
    private YouTubeService youTubeService;

    public VideoStreamingService getBusinessService(String movie) {
        if (movie.toLowerCase(Locale.ROOT).contains("die hard")) {
            return netflixService;
        } else {
            return youTubeService;

The Business Delegate uses a business lookup to route movie playback requests to a suitable video streaming service.

public class BusinessDelegate {

    private BusinessLookup lookupService;

    public void playbackMovie(String movie) {
        VideoStreamingService videoStreamingService = lookupService.getBusinessService(movie);

The mobile client utilizes Business Delegate to call the business tier.

public class MobileClient {

    private final BusinessDelegate businessDelegate;

    public MobileClient(BusinessDelegate businessDelegate) {
        this.businessDelegate = businessDelegate;

    public void playbackMovie(String movie) {

Finally, we can demonstrate the complete example in action.

  public static void main(String[]args){

        // prepare the objects
        var businessDelegate=new BusinessDelegate();
        var businessLookup=new BusinessLookup();
        businessLookup.setNetflixService(new NetflixService());
        businessLookup.setYouTubeService(new YouTubeService());

        // create the client and use the Business Delegate
        var client=new MobileClient(businessDelegate);
        client.playbackMovie("Die Hard 2");
        client.playbackMovie("Maradona: The Greatest Ever");

Here is the console output.

21:15:33.790 [main] INFO - NetflixService is now processing
21:15:33.794 [main] INFO - YouTubeService is now processing

Class diagram

alt text
Business Delegate


Use the Business Delegate pattern when

  • You want loose coupling between presentation and business tiers
  • You want to orchestrate calls to multiple business services
  • You want to encapsulate service lookups and service calls
  • There is a need to abstract and encapsulate the communication between the client tier and business services


Known Uses

  • Enterprise applications using Java EE (Java Platform, Enterprise Edition)
  • Applications requiring remote access to business services



  • Decoupling of Presentation and Business Tiers: Allows the client tier and business services to evolve independently.
  • Location Transparency: Clients remain unaffected by changes in the location or the instantiation of business services.
  • Reuse and Scalability: Business Delegate objects can be reused by multiple clients, and the pattern supports load balancing and scalability.


  • Complexity: Introduces additional layers and abstractions, which may increase complexity.
  • Performance Overhead: The additional indirection may incur a slight performance penalty.