Java Reference
In-Depth Information
This mechanism is a blueprint to access the Application
Server components for the organisation. The architecture does
not allow any Presentation layer components (Command
Handlers in particular) to communicate directly with entities.
Hence only beans that can be accessed remotely are session
beans.
The
mechanism
captures
the
following
architectural
decisions:
•
All
business
service
components
are
implemented
as
Session EJBs or have Session EJB facades.
• A client (in most cases it is a Bean handlers) that requires
access
to
a
Business
service
component
and
creates
an
instance of a Business Delegate.
As a consequence of using two mechanism of framework, the
application has a distinct separation between presentation and
business logic. The boundary is business delegates, which are
smart
proxies
to
business
services
of
application.
This
separation is desirable for few reasons.
• It provides an explicit contract between designers and
developers of presentation tier and the business tier of the
system
• It allows the business tier to change independently from
presentation tier
• It allows for concurrent development of the two tiers.
