I'm trying to find a way to implement an MVC architecture for the situation
where there are multiple distinct Web Users simultaneously accessing a
single model.

Our app schedules employees @ multiple locations. Multiple clients &
schedulers may be accessing each location simultaneously for schedule
information, each having the ability to initiate changes to the schedule.

We anticipate up to 100K employees & 1K locations & are using WebLogic 5.1 &
Oracle8i on Solaris.

I'd like to have a single Controller (Mediator) for each location to mediate
the Users' interface to the Model. Since response time in a dynamic data
environment is critical I thought it advisable to keep the schedule as an
object community under the control of a single-point-of-entry Controller
(Mediator?); this preferred to using Entity Beans for the Schedules'
elements and incurring the EJB and Db-access overheads. The initial thought
was that using a Singleton Controller for each location would be a good
answer but there seems to be scant good info re: implementing this with
J2EE/EJB.

The descriptions I've seen, including Sun's Blueprint Pet Shop app. seem to
consider the Model to be no "deeper" than the User's individual session,
particularly the shopping cart. Everything below that is handled via updates
to the underlying persistent data, allowing the effects of concurrent data
updates to be somehow handled down there. I'm thinking our situation
requires the Model to be much more dynamic, using 'live" objects managed by
the Schedule's controller which are only persisted as required.

Is using a Stateful Session Bean a good strategy? If so, how does the app
ensure that all access to a Location's schedule data occurs through the
single appropriate Controller?

Should we be implementing the Controller outside the EJB container/tier? If
so, should we be implementing another tier to handle these and similar
issues? In this case do we then consider the WebLogic EJB environment as a
whole the Model and migrate coordination and synchronization logic into this
other tier?

Thanks in advance for any help.

Sorry if this is unclear, but it's my first try at describing the situation
without being able to wave my hands and scratch out lots of pictures.

Chris Gerrard

P.S. If it's any help, my OO background is more modeling-oriented than
Db-oriented. It seems that much of the EJB/J2EE info. seems to be developed
from the perspective that the apps are fairly "thin" views and transactional
veneers on top of databases? Is this so, or am I misreading?

===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".

Reply via email to