Re: [ojb-users] OJB in J2EE env

[Thomas M. <tho...@ho...>]

Hi Jiri,

Jiri Luzny wrote:

> Hi,
> 
> we are just evaluating OJB to use it as the persistence engine for our
> project where we consider this scenario: Pure Java Persistent Classes
> within Stateless Session Beans (JBoss).
> After reading the docs and test samples I'm little bit confused what
> API I should actually use.
> J2EE is an environment where concurrent threads will access the same
> persistent object so the ODMG API's locking and transaction
> capabilities should be used here.


If optimistic locking is sufficient for you, you might also use the 
PersistenceBroker API directly. The PB is also thread-safe.

The ODMG level provides object transaction (similar to TopLinks 
Unit-of-work) that you don't have on the PB level.
The faq.html mentions some other things that are not possible on the PB 
level.

If you need those things (object transations, persistence aware 
collections etc.) you should go for ODMG.

If not: use the PB.

> However all EJB examples in OJB use
> PersistenceBroker directly!?
> Can you clarify it?


my ejb sample is rather old. Its also not about session beans, but about 
using OJB in BMP entity beans.


> It would be nice to have an up-to-date guide or examples of usage OJB
> within JE22 app servers.
> 


There is some documentation on this (at least about usage in a 
web-container) in the deployment.html.

There is also a sample for using OJB within a Struts application in the 
contribution download package.

We are currently working on JTA and JCA integration. Once we have 
finished this, we will also provide some documentation about usage in 
J2EE containers.


> Thank you,
> Jiri.
> 
> BTW: I used to work with Toplink in my previous project. The current
> project has smaller budget so we have started looking around for a
> replacement. 
> I was kind of shocked when I figured out that OJB provides almost the
> same functionality and it is open-source! :-)


That's intended! Can you imagine how shocked the TOPLink guys are about 
this ;-)


> Keep up the excellent work!
> 


thanks,

Thomas


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