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Riena / CDO / JPA Integration [message #10633]

Wed, 10 September 2008 13:07

Thomas Kratz

Messages: 165
Registered: July 2009

Senior Member

HI I started an email discussion with christian, which he liked to see
on the newsgroup.

What I want to talk about is JPA Integration. I see many places were
lazy loading in a rich client would be a great thingy to have. I had a
look ad several existing implementations (most of them are aop hacks)
but nothing satisfied me. Christian told me that so far there is nothing
like that in riena. Gavin King from Hibernate has a strong opinion on
why not to remote lazy load which i can understand. I don't know other
JPA implementations but in hibernate lazy loading is very tightly
coupled to the session and all existing solutions break the
transactional philosophy.

what i recently thought about is having something like a remote session
on top of hibernate (as for eg jackrabbit has). that would mean keeping
an entitymanager/session on the server over several client requests.

I would like to hear what you think about that idea, far off from what
it would take to implement something like that. I agree with christian
that approaches like cdo may not scale well in large environments, and I
wonder if keeping thousands of sessions on the server would scale.

Regards
Thomas

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Re: Riena / CDO / JPA Integration [message #10666 is a reply to message #10633]

Wed, 10 September 2008 13:16

Eclipse User

Originally posted by: ekkehard.gentz-software.de

Thomas,

would be great to have a solution for this.

I'm just starting my work to use Riena clients inside my OSGI Enterprise
solution (a german ERP application).
....just focussing on the GUI (Ridgets, databinding, ObjectTransactions)
and so of course I'll run into the Hibernate lazy problem the next weeks ;-)

at the moment my server-side solution is this:

* equinox 3.4
* Riena M4
* EasyBeans OSGI as EJB3 container with Hibernate JPA

I have it all running from server-side and provide my EJB3 Interfaces
from EasyBeans as Riena remote OSGI services

ekke

Thomas schrieb:
> HI I started an email discussion with christian, which he liked to see
> on the newsgroup.
>
> What I want to talk about is JPA Integration. I see many places were
> lazy loading in a rich client would be a great thingy to have. I had a
> look ad several existing implementations (most of them are aop hacks)
> but nothing satisfied me. Christian told me that so far there is nothing
> like that in riena. Gavin King from Hibernate has a strong opinion on
> why not to remote lazy load which i can understand. I don't know other
> JPA implementations but in hibernate lazy loading is very tightly
> coupled to the session and all existing solutions break the
> transactional philosophy.
>
> what i recently thought about is having something like a remote session
> on top of hibernate (as for eg jackrabbit has). that would mean keeping
> an entitymanager/session on the server over several client requests.
>
> I would like to hear what you think about that idea, far off from what
> it would take to implement something like that. I agree with christian
> that approaches like cdo may not scale well in large environments, and I
> wonder if keeping thousands of sessions on the server would scale.
>
> Regards
> Thomas

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Re: Riena / CDO / JPA Integration [message #10698 is a reply to message #10666]

Wed, 10 September 2008 13:56

Ed Merks

Messages: 33137
Registered: July 2009

Senior Member

This is a multi-part message in MIME format.
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Content-Transfer-Encoding: 7bit

In case anyone is interested, since it seems somewhat related, I'm just
finishing off a prototype for generating models that support "native"
java.io.Serializeable:

https://bugs.eclipse.org/bugs/show_bug.cgi?id=245014

I expect there will be a fully functional patch later today.

These would work well in an EJB environment, could be backed by Teneo
(I.e., Hibernate, JPOX, JPA and EclipseLink), and integrate well with
data binding... Of course we could generate such things from a .xsd and
produce conforming XML serializations as well...

ekke wrote:
> Thomas,
>
> would be great to have a solution for this.
>
> I'm just starting my work to use Riena clients inside my OSGI
> Enterprise solution (a german ERP application).
> ...just focussing on the GUI (Ridgets, databinding,
> ObjectTransactions) and so of course I'll run into the Hibernate lazy
> problem the next weeks ;-)
>
> at the moment my server-side solution is this:
>
> * equinox 3.4
> * Riena M4
> * EasyBeans OSGI as EJB3 container with Hibernate JPA
>
> I have it all running from server-side and provide my EJB3 Interfaces
> from EasyBeans as Riena remote OSGI services
>
> ekke
>
> Thomas schrieb:
>> HI I started an email discussion with christian, which he liked to
>> see on the newsgroup.
>>
>> What I want to talk about is JPA Integration. I see many places were
>> lazy loading in a rich client would be a great thingy to have. I had
>> a look ad several existing implementations (most of them are aop
>> hacks) but nothing satisfied me. Christian told me that so far there
>> is nothing like that in riena. Gavin King from Hibernate has a strong
>> opinion on why not to remote lazy load which i can understand. I
>> don't know other JPA implementations but in hibernate lazy loading is
>> very tightly coupled to the session and all existing solutions break
>> the transactional philosophy.
>>
>> what i recently thought about is having something like a remote
>> session on top of hibernate (as for eg jackrabbit has). that would
>> mean keeping an entitymanager/session on the server over several
>> client requests.
>>
>> I would like to hear what you think about that idea, far off from
>> what it would take to implement something like that. I agree with
>> christian that approaches like cdo may not scale well in large
>> environments, and I wonder if keeping thousands of sessions on the
>> server would scale.
>>
>> Regards
>> Thomas

--------------000609090606080802050402
Content-Type: text/html; charset=ISO-8859-15
Content-Transfer-Encoding: 8bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-15"
http-equiv="Content-Type">
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<body bgcolor="#ffffff" text="#000000">
In case anyone is interested, since it seems somewhat related, I'm just
finishing off a prototype for generating models that support "native"
java.io.Serializeable:<br>
<blockquote><a
href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=245014">https://bugs.eclipse.org/bugs/show_bug.cgi?id=245014</a><br>
</blockquote>
I expect there will be a fully functional patch later today.<br>
<br>
These would work well in an EJB environment, could be backed by Teneo
(I.e., Hibernate, JPOX, JPA and EclipseLink), and integrate well with
data binding...

Ed Merks
Professional Support: https://www.macromodeling.com/

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