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From "Chanda Fake" <>
Subject Re: Using Cayenne in GWT wthout DTOs
Date Sun, 21 Sep 2008 14:09:21 GMT
Thanks all for your input. Learnt something and will pick it from here. I
just thought maybe there could have been something similar to hibernate4gwt
in the hibernate land. Maybe I could work on something.

Good day


On Wed, Sep 17, 2008 at 8:04 PM, Scott Anderson <>wrote:

> This topic has been discussed in this group before, but I'll reiterate
> the general concepts. You can't serialize persistent objects, period.
> There are many reasons why, but I don't have time to list them all, so
> here are the three that are most important in my mind.
> Reason #1:
> In order for the GWT compiler to transform your CayenneDataObjects in to
> JavaScript, it would have to resolve a graph that would encapsulate the
> entire Cayenne library. I could list the reasons why you can't do that,
> but I don't have time to write an essay right now, so save yourself the
> headache by taking me at my word when I say it won't work.
> Reason #2:
> The purpose of the server-side code is to enable validation and
> authentication. You can expose un-verified, un-authenticated database
> access to the client-side code without RPC. If you're not going to
> validate or authenticate, don't bother introducing the proxy. Cayenne
> will work just as well in a stand-alone application -- the Modeler is a
> good example of that.
> Reason #3:
> By writing the code to copy information out of beans and in to the
> CayenneDataObjects, you will be forcing yourself to plug any validation
> holes you would otherwise surely forget. Additionally, by using beans
> targeted to the needs of your operations, the amount of data that is
> required to go back and forth through the RPC tunnel will be
> substantially lower.
> If you were to serialize the CayenneDataObjects, which is impossible,
> then for *every* operation you'd have to send the entire graph of the
> object in question -- which is probably the entire database if you
> reverse-map your relationships.
> Hope this helps,
> Scott
> -----Original Message-----
> From: Chanda Fake []
> Sent: Wednesday, September 17, 2008 1:07 AM
> To:
> Subject: Using Cayenne in GWT wthout DTOs
> Hi
> I have seen from the mailing list that some people have used Cayenne
> with
> GWT successfully.What is the best way to expose Cayenne model to GWT
> without
> using DTOs which I consider as duplication of work. Am trying to use my
> Cayenne domain objects in GWT and running into some  usual issues GWT.
> Am
> thinking if there is a way to create a module with the offending class
> "CayenneDataObject" and then including it using <inherits ..>. What have
> others done.
> Thanks in advance

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