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Home » Eclipse Projects » EclipseLink » Using cache-coordination across different eclipselink version(Is it feasible to use cache-coordination across several nodes running different versions of eclipselink)
Using cache-coordination across different eclipselink version [message #1722227] Wed, 03 February 2016 14:25 Go to next message
Thom Park is currently offline Thom ParkFriend
Messages: 12
Registered: June 2012
Junior Member
We have several different applications that access common data via eclipselink.

We'd like to move from our current version (2.2) to the latest version (2.6+) however we've discovered our older applications do not function correctly using later versions of eclipselink. (we've tried 2.4,2.5 and 2.6 and run into difficulties)

An option under consideration is to leave the older applications on the 2.2 version of eclipselink and move the newer applications (that work against later versions) to the latest release.

We do, however, rely on cache-coordination to maintain the identity map across the various applications. Which brings me to the question:

When using cache-coordination to maintain integrity of a distributed cache, do all nodes have to be on the same release of eclipselink?

Does anyone know, for sure, if this is supportable, or is it a fools errand to even consider this feature with differing versions of eclipselink?


Re: Using cache-coordination across different eclipselink version [message #1722862 is a reply to message #1722227] Tue, 09 February 2016 18:52 Go to previous messageGo to next message
Chris Delahunt is currently offline Chris DelahuntFriend
Messages: 1380
Registered: July 2009
Senior Member
It might be supportable, but the changesets that are passed around are not guaranteed to be backward/forward compatible. If this is the route you want to look into, I would use cache invalidation as there will be less changes in this functionality between versions.

Sending around changesets may have some changes with the versions, but the cache-coordination classes are extensible, and you can even write your own listener to customize how what is sent around is handled rather then letting old/new EclipseLink classes break with incompatibilities. Making these changes and testing the integration might be as much work as fixing the app to run against EL 2.6 though.

Best Regards,
Re: Using cache-coordination across different eclipselink version [message #1723222 is a reply to message #1722862] Fri, 12 February 2016 15:08 Go to previous message
Thom Park is currently offline Thom ParkFriend
Messages: 12
Registered: June 2012
Junior Member
Thanks for the reply Chris - I appreciate it.

The 2.2 based app is mired (and I use that work intentionally) in it's use of the old Toplink v1 API. All of the (very many) Entities have ValueHolderInterface definitions to support the non-transparent one-to-many relationships on the system.

Were it not for this, we could certainly move the newer apps on to 2.6 and JPA. However, because a non-JPA entity has ValueHolders and the JPA-based entities would not have ValueHolders defined in the entity, I'm at a loss to move my app to 2.6 and JPA without having to rewrite everything that shares the common database an entity sets.

If you have any experience in sharing v1 based entities with JPA based entities (I understand that ValueHolders still get weaved in behind the scenes in JPA) I'm curious if an entity called that's defined with Valueholders in one application would be compatible with a similarly named entity in the other application but lacking Valuholders in the entity definition (due to the use of JPA annotations).

Would the objects 'look' the same as far as a distributed cache is concerned - i.e. in the cache of the JPA app, would the object hold a collection of entities, or would it hold a value holder?

Hmm. I've deviated quite a bit from the topic - maybe I should repost as a different question.

[Updated on: Fri, 12 February 2016 15:09]

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