Re: Enterprise using WO

Hi Ashley,

>
> WO + Hibernate?  That's an interesting combination.
>
> Can you please explain why you chose to use Hibernate rather than  
> EOF?  Is it because Hibernate works with POJOs rather than  
> subclasses of EO?
>

We are using Hiberate now for several reasons:
1) Every Java Software Factory I've been in contact with is using it,  
and you can get people already using the tool in several domains

2) The current and future EJB spec is going towards the POJO model  
based on Hibernate (at least Gavin King -Hibernate's father- is in  
the J2EE JCP). Maybe then I will use EJBs :-)

3) EOF is great but it has an architectural problem that I guess is  
based on the fact the EOF was initially conceived as a desktop 2 tier  
client server architecture. In particular I am talking about the way  
EOF handles database connections. EOF was not designed to share a  
pool of db connections among users. You can actually achieve that by  
replicating the EOF stack (one per user , or one shared among some  
users) but by doing that you are replicating the EOF cache, nasty.  
Once you replicate EOF stacks you break optimistic locking unless you  
provide a change notification mechanism among stacks, nasty again.  
Same happens when you deploy several instances of the app (you always  
do that).
Having to subclass EO is not a problem for me although I understand  
that it can be for others.

BTW another option is to use Andrus Adamchik's Cayenne ORM. (Thanks  
him again for the amazing WOLips magic!)
We had initially evaluated Cayenne as an alternative and we are still  
evaluating it as a replacement for our EOF stuff. As he himself tells  
me in an email the transition from EOF to Cayenne should be smoother  
than to Hibernate.
But back to point (1), I can get developers with Hibernate knowledge  
in the market right now.

The fact is that if Apple redesigns EOF architecture I will be  
definitively using it again. In fact I am just about to formally  
request that to an EOF engineer I've met in the last WWDC.


> Also, why did you choose a Web interface for a factory automation  
> system?  I am just curious about your application / domain.
>

We wanted to be able to access the tool using a web browser from  
anywhere. The presentation layer is simple and provides basic  
configuration functionality (no complex CRUD) and servers mainly as a  
monitor with charts and semaphores. The rest of the configuration is  
done in the SCADA system provided by Siemens.

Context: We are talking about a cigarette manufacturing plant. Not a  
very complex domain per se.


Alejandro M. Ramallo
IT & Relationship Management Director
Nobleza Piccardo S.A.I.C.yF. (BAT Group)