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From John Huss <johnth...@gmail.com>
Subject Re: Use same entity classes for server and ROP client
Date Thu, 22 Sep 2011 03:19:30 GMT
I got this to work today after some experimentation.  My app is a client app
that normally connects to a remote server, but can also run offline by
connecting to a local DB.  So the client will have the model / map files
present locally to enable the offline mode.  Since the model is available,
CayenneDataObject can be used as the common base class (with a little
work*).  CayenneDataObject is not that different from PersistentObject (it
is a subclass of it after all).  The primary difference is the presence of
the validate methods, and those require access to the DbEntity info
contained in the model.  I also was able to get a version working based on
PersistentObject for both the client and server, but I chose to stick with
CayenneDataObject since it is more standard and more full-featured.  So I
think I'm good to go now.

* The little work is replacing the entity resolver on the client with an
entity resolver obtained from a ServerRuntime (for the local offline db),
and making sure the server doesn't use the client entity resolver when
sending data to the client.  If anyone is interested I can share some more
 specific code.

John

On Wed, Sep 21, 2011 at 7:50 PM, Aristedes Maniatis <ari@maniatis.org>wrote:

> On 21/09/11 12:37 PM, John Huss wrote:
>
>> I'm try to find out if I can make a single app that can work either with a
>> local DB or using ROP with a remote DB.
>>
>> For the ObjectContext it looks like as long as the code uses the
>> ObjectContext interface that should allow to code to run against either
>> and
>> there doesn't seem to be much loss of functionality from just using the
>> interface.
>>
>> But for the entities it looks like the client should use PersistentObject
>> subclasses and the server should use CayenneDataObject subclasses, and
>> PersistentObject is missing some useful methods.  So I'm wondering what in
>> CayenneDataObject prevents it from being used on the client, or what in
>> PersistentObject prevents it from being a good fit on the server.  What is
>> the best way to end up with a single set of classes that supports both?
>>
>
>
> We have had the exact same issues and ended up with separate classes for
> client and for server. And of course plenty of interfaces and helper classes
> to share common business logic. We are also thinking about creating a single
> user application with the server and client code merged into one
> application: when we get around to that, I think the approach will be to
> continue to use ROP, but short circuit the connection between client and
> server so it doesn't need to travel over Hessian/Jetty. Hopefully we'll be
> working on that in a month or so.
>
> Regards
> Ari
>
>
>
> --
> -------------------------->
> Aristedes Maniatis
> GPG fingerprint CBFB 84B4 738D 4E87 5E5C  5EFA EF6A 7D2E 3E49 102A
>

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