Cant we use the commandHandler itself to shield the presentation layer from the possible volatility as mentioned above ?
My doubts come after reading sun's blue-print.May be i dont quite understand it.
Typically as per Sun's Blue-prints, they have shown a Class Diagram
which depicts using both FrontController-->CommandPattern->Session Facade
and also a Business Delegate. The Business Delegate is being used only during data retrieval part.
They clearly mention that one shud use Business delegate when you are trying to retrieve data (Read). I am not quite convinced. Why cant we do without Business Delegate and use the same architecture of FrontController-->CommandPattern->Session Facade-->Business Delegate-->Business Objects for retreiving data.
As per sun's blueprint the explanation for using Business Delegate quite like Alur..But what is confusing me is that Business Delegate is not being used when request is coming via controller-->command-->sessionfacade-->business object. But only during retrieval.
You can refer to the explanation the above mentioned URL.
Any ideas here ?
Originally posted by vu lee:
The controller creates an event, which is a command, then passes the event to the EJB controller which is a stateless session bean. In my opinion, if business delegate is being used, it should have been used here to decouple web tier from ejb tier.