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From "Dr. Michael Lipp" <Michael.L...@danet.de>
Subject Serious design flaw
Date Tue, 09 Aug 2005 12:48:47 GMT
Hi,

I have spent quite some time now with OJB and found a serious problem
that will -- I'm afraid -- prohibit me from using it.

The problem comes up when OJB is used in a framework (Jetspeed2 in my
case) and the application (read portlet) wants to use OJB as well -- but
with a different configuration. Specifically, the framework uses some
ConnectionFactoryClass that comes with Spring and looks for Spring Beans
with names identical to the JCD-Alias. I'm not using Spring in my
application and therefore need another ConnectionFactoryClass (I would
have created the Spring Beans as a workaround, if only I could reach the
Spring BeanFactory used by Jetspeed; but of course, I cannot get this;
and even if I could it would make my program depend on Jetspeed2 which I
do not want it to be).

Now, due to the fact that OJB uses a lot of static classes and
singletons, I cannot use an alternate OJB configuration for my
persistence. What OJB lacks -- and this I consider a design flaw -- is
the possibility to create a ConnectionFactory instance, configure it,
use this to configure a PersistenceBrokerFactory instance and use this
to obtain a PersistenceBroker. This would enable me to use different OJB
configurations in parallel (without doing classloader tricks which is
not really an option in the J2EE environment).

I have looked at the code. I could write a PersistenceBroker wrapper
that overrides the serviceConnectionManager() method. But all
ConnectionManager implementations obtain the ConnectionFactory -- again
-- from using something static and they have no "setConnectionFactory"
method. So I'd end up implementing my own ConnectionManager. While, of
course, I can copy the code, this is really not what I expect from a
well designed framework.

Regards,

    Michael

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