On 05/12/2007, at 7:46 AM, Adrian Wiesmann wrote:
So here is my problem. While I would like to keep the embedded
database
for single user scenarios, I would also like to use ROP for multi user
environments.
Can I implement both and switch from one to the other mechanism with a
simple (to be implemented) configuration switch? From what I read in
the
documentation Hessian uses a new ObjectContext? That is probably the
easy
part. But what about client and server code in the client? Can I mix
this?
Or is there some simple trick?
We have exactly the same scenario with many of the same choices:
Derby, ROP, etc. We used Jetty for the servlet container and that
worked really well. We have Derby embedded in the server application.
But we've never written a single merged client/server app.
There is quite a lot which is different at the moment between client
and server in Cayenne. The entities do not subclass the same Cayenne
entities (PersistentObject/CayenneDataObject), so you'll find it very
hard to write a single set of code which works interchangeably as a
single application and also as client/server, unless internally you
continue to use Cayenne ROP/Hessian. You can't easily write code which
works both on Cayenne client and also on the server. Apart from the
class hierarchy some other things are different: no nested contexts on
the client, different behaviour of lifecycle events, etc.
I guess you could connect the client to the server at 127.0.0.1 and
make it work like that, even if the client and server are compiled
together into a single application. It would be interesting to see
which parts you might be able to strip out. I could imagine ways you
might be able to remove Jetty from the picture and hook the client and
server bits directly together.
Ari
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