Re: [ozone-dev] Ozone and jBoss

[Daniel Schulze <daniel.schulze@telkel.com>]

Hi Folks,

time for me to say something ;-)

I had a close look to the CMP2.0 spec. Because the EJB1.1 stuff is
actually running well on top of RDBMSs, I ve tried to find an advantage
in using Ozone in a CMP2.0 environment (IMHO: the first generation of
real life proof EJBs).  
Hmmmm..., the spec is not that kind of _ready_ to implement yet, so 
I currently work on other things...

When I understand your approach Peter, then you just try to put Ozone
in the jBoss environment and let the container use it as an ordinary
database. You could model (automatically generated) a persistent object
class for your bean class and a home object class for this class. In the
home object you implement the finders and create methods, so that
actually only the home objects are root objects in Ozone (I m clear?).

But I m not very happy with this approach, because the EJB client calls
then a proxy which calls a proxy which...

I think the most clean solution would be a separate entity container
especially for Ozone _embedded_ in jBoss. But this of course is a real
big *** of work :-(

So maybe these days its better to use the advantage of a ODBMS as O3
is where it is needed and use EJB for simple things... ;-)
(The CMP2.0 spec is not that OO as we hoped - it still
smells like RDBMS) 

Hope I wasnt too discouraging...

bye Daniel

PS: Greetings to the SMB team from the other side of the ozean!


On Fri, 06 Oct 2000, you wrote:
> Hi,
> 
> Thanks to Gerd for the reply.
> 
> For finders in EJB, you would typically write something like:
> 
> Enumeration findByPrimaryKey( CustomerPK key );
> Enumeration findBySurname( String surname );
> 
> on a Customer bean whos primary key is CustomerPK class. The return value is
> the set of Customer objects which satisfy the given criteria.
> 
> In your opinion, is it possible to use such methods for finding objects with
> Ozone as it stands at the moment?
> 
> Thanks,
> 
> Peter.
> 
> ----- Original Message -----
> From: "Gerd Mueller" <gerd@smb-tec.com>
> To: <ozone-users@ozone-db.org>
> Sent: Wednesday, October 04, 2000 8:16 AM
> Subject: Re: [ozone-dev] Ozone and jBoss
> 
> 
> >
> > Hi,
> >
> > > I have been charged with looking at integrating Ozone and jBoss with
> regards
> > > to implementing Container Managed Persistence (CMP). I am not sure,
> however,
> > > that Ozone is a good choice and I would like some opinions.
> > >
> > > First of all, is it even possible? Bare in mind that for EJB support,
> you
> > > must be able to execute 'finder' queries which return result sets. That
> > > means a query language and I believe Ozone doesn't have one, navigation
> (I
> > > presume) being done by well known root objects and persistence by
> > > reachability.
> >
> > That's right, at the moment there is no query language but as you may have
> > noticed there are discussions in the ozone-users list about that. I'm not
> that
> > familar with EJB, so I don't know what is necessary for 'finders'. Do we
> really
> > need an query language for that ? If yes, it could be really difficult to
> use
> > ozone for CMP at the moment.
> >
> > > If it is possible, has anyone tried to do something similar with it
> already?
> >
> > As far as I know you are the first one :)
> >
> > > Basically, I'm looking for opinions on how Ozone could be used for CMP
> if at
> > > all. Any help would be appreciated. Also, since jBoss is now part of a
> fully
> > > commercial supported product called openJoda, it would do Ozone no harm
> to
> > > be associated with jBoss.
> >
> > Best Regards,
> > Gerd
> >
> > --
> > ________________________________________________________________
> > Gerd Mueller                                    gerd@smb-tec.com
> > SMB GmbH                                  http://www.smb-tec.com
> >