This pattern solves common problems described below;
-Mapping OO design to J2EE architecture.
-Decrease network cost or chattiness of the application.
-Light weight object creation improves response time.
-Benefit of C++,OO and Corba skill usage.
-Chance of easy migration to Corba when J2EE trend becomes unsuccessfull.

This pattern may sound interesting but applicable. We are using it in a large 
enterprise system development project - in replacement of a mainframe system which 
operates a complete wholesale bank with all fuctionality-. And, we are satisfied with 
results.
After we have worked nearly a year for analysis and design we got a huge OO design 
with UML in Rational Rose. During this period of time our architects decided to use 
Java and EJB as architecture. In spite of the increased popularity of EJB technology 
we could not find answer below design problems;
-When all objects were implemented as EJB, network cost would be increased.
-When Aggregate Entity Pattern is choosen, error prone, labor intensive code would be 
increased.
-Relying the discussions about EJB patterns and architecture, nobody knows the answers 
in this architecture , especially developing enterprise system.

So, we choosed below layered structure;

Client
-UIML based generic applet

Web Server
-Servlet as presentation manager

Application Server (Business Layer : Session EJB+dependent objects)
-Caller Object as Business Service Supplier(calls Stateless Session EJBs)
-Light Stateless Session EJBs as wrapper for dependent business java plain objects. 
All business object hierarchy is implemented with plain java objects (very huge) which 
are created inside wrapper session EJB. Briefly, we built a class layer between 
Session EJBs and Entity EJBs.

Application Server (Data Layer )
-Fine grained CMP entity EJBs

Application Server schema:
----------------------------------

Caller object || Wrapper Stateless Session EJB || Class Layer || Fine grained CMP 
entity EJB

----------------------------------
All commands and suggestions are welcome.

Ghari,






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