Re: [science-iwg] A technical question : status of eclipselink / gemini

[Erwin de Ley <erwin.de.ley@xxxxxxxxxx>]

Thanks Mike.

To be more clear : it's not about having eclipselink available as a set of bundles, that's available and OK.
It's about using a persistence layer in a typical modular OSGi-based application architecture, with dynamic/modular entity registrations (comparable to the dynamism of OSGi services e.g.).
This doesn't seem to be possible with the current state of eclipselink nor Gemini JPA (nor the current OSGi JPA spec that is often referred to).

But it's also about a more general situation, where it seems that the main JPA-related projects at eclipse are not actively pursuing/advancing OSGi applications, unless I misunderstand things.
(while JPA is a major thing in many enterprise software systems)

Eclipselink has removed its support to be integrated in an OSGi application it seems, and has delegated that support to Gemini JPA.
But Gemini JPA has all kinds of constraints (e.g no support container-managed persistence if we would like to build Java enterprisey solutions) and is no longer evolving since 2013.
This means it's not a valid candidate for many application domains and deployment strategies where we would like modular systems (and based on OSGi).

Even if the OSGi JPA spec does not (yet?) support the requested level of modularity/dynamism for entities, or there are class-loading difficulties to resolve or ... : is this recognized as a strategically important issue that should be investigated/resolved?
As eclipse is a major OSGi-oriented community, it would be a good place to push this forward towards modular application architectures?

It is our opinion that eclipselink, being a leading JPA implementation (reference implementation), can not rely on a dead project for a crucial use case, especialy when being part of the eclipse ecosystem.

If this is seen as important, we may be able to collaborate on getting something implemented.
We've got experience in-house in this domain, implementing such dynamic entity handling on pre-LUNA eclipselink.

Some related info :
https://www.eclipse.org/forums/index.php?t=msg&th=365382
https://www.eclipse.org/forums/index.php/t/457852/
https://www.eclipse.org/forums/index.php/t/1072331/
https://www.eclipse.org/forums/index.php/t/639835/
http://wiki.eclipse.org/Gemini/JPA/Documentation/Limitations
https://wiki.eclipse.org/EclipseLink/Examples/OSGi

https://bugs.eclipse.org/bugs/show_bug.cgi?id=399854 (from 2013)
https://bugs.eclipse.org/bugs/show_bug.cgi?id=363195 (from 2011)


cheers
erwin

Met vriendelijke groeten - Bien à vous - Kind regards

Erwin De Ley

---

Tel. +32 9 335 22 10 fax: +32 9 335 22 19 erwin.de.ley@xxxxxxxxxx

iSencia Belgium Voorhavenlaan 31 bus 11 B-9000 Gent www.isencia.be

 

Op 04/02/2016 om 11:59 schreef Mike Milinkovich:

Adding Doug Clarke (EclipseLink Project Leader) to this, as he would be the guy who actually knows what's going on. Doug - What is the state of EclipseLink being available as an OSGi bundle? (I think you'll have to subscribe to the list to reply) On 04/02/2016 2:46 AM, Erwin de Ley wrote:

Dear all, Triquetrum's goal is to be an open and extensible platform itself, but also to be able to deliver plugins that can easily be integrated in other such platforms. And the typical shape will be an RCP application I guess. (we'll also deliver headless components, but this is even irrelevant for the issue described) At some point in the near future, we'll start integrating a persistence service, preferably based on JPA. We will need to be able to provide & register entity implementations from our bundles, while also allowing other bundles to do the same. And without blocking the possibility that they should belong to the same persistence unit. (e.g. cases where extensions provide entity subclasses that must fit in one of the normal mapping strategies, or where there are associations mapped to foreign keys etc) But there seem to be some issues with the current state-of-affairs to use a JPA implementation in an OSGi/RCP setup, in a modular way. I.e. it is required that there is one-persistence-bundle-to-rule-them-all that registers all entities in one shot. This of course does not fit our needs (as also for many other modular systems, for which OSGi is meant) Furthermore it even seems that eclipselink, since some time, no longer targets an OSGi runtime, and that their support for this has been moved to Gemini JPA. But Gemini JPA seems quite dead : a milestone that remains unfinished since a couple of years. Does anyone have any experience in this? There are several old-and-more-recent forum posts and bugzilla tickets open in this domain, but there seems to be no evolution/solution in the 2 mentioned eclipse projects. Is there some effort/stretegy on some eclipse foundation PMC level or so, to determine what the strategy is related to JPA/OSGi/eclipse/modularity? thanks erwin _______________________________________________ science-iwg mailing list science-iwg@xxxxxxxxxxx To change your delivery options, retrieve your password, or unsubscribe from this list, visit https://dev.eclipse.org/mailman/listinfo/science-iwg

-- Mike Milinkovich mike.milinkovich@xxxxxxxxxxx +1.613.220.3223 (mobile)

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