Win a copy of Re-engineering Legacy Software this week in the Refactoring forum
or Docker in Action in the Cloud/Virtualization forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

Why so much emphasis on Business Delegate or Intercepting Filter

 
Sam Gehouse
Ranch Hand
Posts: 281
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I am not sure why so much emphasis is placed on Business Delegate and Intercepting Filter in SCEA postings.

The reality is, WebClient app and think client apps are two separate apps which are deployed separateley.

However, they will use the same SLSB and DAO.

If they are two separate apps, where is the need for Business delgate?

No delegation is necessary as one app (web app) will hit Servlet and the web UI will hit Servlet and the other app (thick client) will hit POJO.

Am I missing anything?
 
Jacek Ostrowski
Greenhorn
Posts: 23
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Sam,

From http://java.sun.com/blueprints/corej2eepatterns/Patterns/BusinessDelegate.html

Reduces Coupling, Improves Manageability
The Business Delegate reduces coupling between the presentation tier and the business tier by hiding all business-tier implementation details. It is easier to manage changes because they are centralized in one place, the Business Delegate.


This is why BD is so important.

Jacek
 
Sam Gehouse
Ranch Hand
Posts: 281
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I agree with you and fully understand the benefit of Business delegate.

I should have asked the question differently. My question is:

As two separate applications are deployed (one web, another Swing) with both using the same SLSB and DAO; I think I do not have to use Business Delegate.

Any input?
 
Jacek Ostrowski
Greenhorn
Posts: 23
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
It doesn't matter how many apps you have.
For some apps BD is useful, for others is not.

Here I would use BD to reduce coupling between tiers and
I would share BD between both apps.

Jacek
 
Yi Meng
Ranch Hand
Posts: 270
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
As you may already be aware that Business Delegate is used between Systems ...not just between UI and Business layers..

Therefore, what if FBN switches to a different credit card gateway later on?
 
Francesco Bianchi
Greenhorn
Posts: 5
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Does it means that the BD and the Service Locator are a part of the Java Application client?
 
Meghana Reddy
Ranch Hand
Posts: 76
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Originally posted by Francesco Bianchi:
Does it means that the BD and the Service Locator are a part of the Java Application client?


Nope , they ain't part of either the app client/web client or the business app.

BD is the point of seperation of Client and the enterprise/biz app. BD completely abstracts the app client of any of the biz app changes.
BD is the one that would undergo changes if Business interface changes.

SL just implements a lookup mechanism for remote objects.

So, these are not part of the app client as they can serve any of the Client applications.
 
Pham Huy Anh
Ranch Hand
Posts: 41
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hello,

As I understand, Business Delegate is like interface, which expose the "contract", the face of functionality. And the change of implementation doesn't impact (very much) BD.

In other word, Business Delegate is the front part of component.
Is that right?
[ May 10, 2007: Message edited by: Pham Huy Anh ]
 
Frank Kuepper
Ranch Hand
Posts: 45
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
In a way, yes.
A Business Delegate is a proxy (see GoF pattern) for the ejb hiding the complexity of lookup and access (remote or local).
 
Don't get me started about those stupid light bulbs.
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic