[OJB-developers] JNDI data stores

[Kim A. <ki...@de...>]

Hi,

(I've already posted this on the sourceforge forum...)

I'm currently evaluating OJB for use in our current project - and I'm very
impressed by the overall performance, feature set and neat design. However,
we are planning to support "transparent persistence" not only with a RDBMS
backend but want to use LDAP (via JNDI) as a data store. Why? Let me
explain our scenario:

We have a web application that has different "realms" where only
authenticated users (belonging to a certain group) are granted access
rights. Let's say, the company running the web application keeps all of its
employees along with groups (such as "Marketing & Sales", "Public
Relations", etc.) in a LDAP directory. However, the data of the company's
customers is NOT kept in this directory but in a different, RDBMS-based
system. The customers should have access to a certain realm within the web
app and therefore must be authenticated against the RDBMS.
I'm now thinking of the following algorithm to accomplish this:

 - I have an abstract class "User" that serves as a base class
 - I have the concrete classes "Employee" (that is made persistent using
   LDAP) and "Customer" (that is made persistent using a RDBMS)
 - Based on the realm I can decide whether to use "Employee" or "Customer"

No problem so far as long as: 1. I implement "Employee" using the
"BMP"-pattern (that is, implementing the persistence mechanism in the
"Employee"-class itself) and 2. the company employee data is kept in LDAP.
If I have to deploy the app in another environment, where no LDAP service
exists and the employee data is kept in a RDBMS, I will have to
re-implement "Employee".

So I wondered if it would be possible if the persistance layer iself could
do the job for me and decide in which data store to look based on its
configuration for a particular environment. Unfortunately, no one seems to
have implemented this already AFAIK. However, after looking through the OJB
sources I found it wouldn't be that hard to "plug in" such a feature by
implementing my own ojb.broker.PersistenceBroker. Sure, there would be some
issues with transactions and relational logic but I think a solution can be
found for this...


Now my questions:

Has anybody heard of some software doing this already?
If not, what's your opinion about building such a thing into OJB?
Anyone interested in implementing it or just discussing it with me?


I'm looking forward to any comments.

Regards,
Kim