Scott,
Thanks so much for the input. It's exactly what I was looking for.
Honestly, I wasn't entirely sure of the approach, either. It seemed
to me to make sense that since we have a data object such as a
"Campground" that Cayenne has already defined for us, that we would
reuse this object in our web service layer, as well. I did consider
the fact that this object's purpose was more specific for ORM
purposes, but it seemed that it might be useful as a general purpose
definition of a given entity. However, you do raise some good points
I hadn't considered about validation. I guess I thought we might be
able to add that validation to the data object itself, but perhaps not.
I am prepared to implement the bean classes necessary, I just thought
it worthwhile to explore the possibility of marshaling cayenne data
objects into XML for use directly with our web services. If anyone
else has any further input on the matter, please let me know. Do
Hibernate or Toplink classes work the same way? Does anyone use these
classes like I'm suggesting? Anyway, let me know and thanks again for
the input!
--
Jon
Jon Sharp
CTO & Senior Engineer
Campground Automation Systems, Inc.
[EMAIL PROTECTED]
(615) 579-5868
www.campgroundautomation.com
On May 28, 2008, at 3:13 PM, Scott Anderson wrote:
On a side note, if you really wish to expose the persistence layer
directly to the client, you might consider building cayenne directly
in
to your application, and avoid the middleman.
As I see it, the whole point of having a WS is to validate data before
it hits the database.
-----Original Message-----
From: Scott Anderson [mailto:[EMAIL PROTECTED]
Sent: Wednesday, May 28, 2008 4:05 PM
To: user@cayenne.apache.org
Subject: RE: Cayenne and JAX-WS / JAXB
Jon, what is the reason you wish to do this? What you're proposing
breaks the whole point of making a layer out of persistence; it is
taboo
to even speak of serializing your persistence layer in any direction
other than to or from the database, which is what Cayenne does for
you.
Consider what might happen if you were to take a persistence object
off
the wire and put it in to the database without validation of both the
data, and credentials. The last thing you want is for a typo or a NULL
relationship to result in the cascading nuking of foreign keys.
The standard approach is to create serializable "beans" of a similar,
but in reality generally more simplistic, structure to your database.
This restricts any possibility of transferring information that is not
intended to be sent to the client, and forces you to validate all
incoming data. Since you should be validating all incoming data
anyways,
it won't be any extra work for you to take this step.
Regards,
Scott
-----Original Message-----
From: Jon Sharp [mailto:[EMAIL PROTECTED]
Sent: Wednesday, May 28, 2008 3:30 PM
To: user@cayenne.apache.org
Subject: Re: Cayenne and JAX-WS / JAXB
Andrus,
Thanks for the input. I've been playing around with this annotations
approach, but it seems I'm going to have to get into the cayenne
source a bit more than I expected. It looks like I'll need to
annotate the Interfaces themselves (DataObject). I've checked out the
latest Cayenne trunk, but have had some trouble with it. I'll see if
I can't find a milestone to work from. In the meantime, as I see it,
this may be a real benefit to Cayenne to allow for XML serialization
of Cayenne data objects using JAXB. I imagine this would be a popular
feature for many, whether implementing web services or not. If I'm
going to put resources on this on our end, I'd certainly be interested
in feeding these changes into Cayenne proper. What do you guys
think? Is this as good a solution as I think it might be? I'd love
to hear any input on this. And perhaps the dev list is a more
appropriate place for this discussion.
Thanks again,
Jon
--
Jon Sharp
CTO & Senior Engineer
Campground Automation Systems, Inc.
[EMAIL PROTECTED]
(615) 579-5868
www.campgroundautomation.com
On May 27, 2008, at 3:01 AM, Andrus Adamchik wrote:
I never used JAXB, although I evaluated it briefly in the past. With
everyone gradually moving to Java 6, it probably warrants a closer
looks from us in Cayenne. More to the point, I think the annotations
approach should work, but that will require some experimentation. So
try it, and let us know if you run into any troubles.
Andrus
On May 27, 2008, at 2:51 AM, Jon Sharp wrote:
Hello all,
We are using Cayenne 3.0M3 for ORM in our project and are exposing
this database using SOAP Web Services. We're using the latest Sun
Metro stack (1.2), consisting of the JAX-WS and JAXB frameworks.
In attempting to use Cayenne Data objects as either return types or
method parameters for our defined @WebMethod's, we are greeted with
an error that indicates JAXB does not handle interfaces. For those
who may not be familiar with JAX-WS/JAXB, JAXB is responsible for
marshalling java objects into XML, and this is of course necessary
for use in SOAP web services provided by the JAX-WS framework.
According to https://jaxb.dev.java.net/guide/
Mapping_interfaces.html, there are some solutions for this issue,
but it appears that it may involve code changes to Cayenne. I'm
not a Cayenne developer, so I cannot say how feasible or practical
this approach may be. Perhaps someone could comment on that, but
more important to me at this point is determining whether anyone
has been successful in marshalling cayenne data objects to XML
using JAXB?
Thanks,
Jon
--
Jon Sharp
CTO & Senior Engineer
Campground Automation Systems, Inc.
[EMAIL PROTECTED]
(615) 579-5868
www.campgroundautomation.com
