Hi Andrew!
When I did my first evaluations for a new project 3 years ago. Back then I was
checking out the sources fo EclipseLink, Hibernate and OpenJPA.
EclipseLink just didn't cut it at all. From what I've heard, the Eclipse
community now rewrote a huge part of the code already, but they are imo still
quite a few miles away from being production ready. I have honestly no idea how
it could have become the RI for JPA...
Hibernate is much better. It basically works pretty well and is also relatively
fast. There is only one thing which I don't like that much and this is their
subclassing approach for 'enhancement'. This has a few nasty side effects and
you need to know them.
I finally picked OpenJPA because it was (in my tests) the only JPA provider
which was able to reliably serialize/deserialize entities without loosing state
or trashing the database afterwards. I really need this because we have a real
cluster environment and peak 5 mio page hits/day in our app, so not being able
to serialize is a knock out. Of course you need a few magic properties in your
persistence.xml:
property name=openjpa.DetachState value=loaded(DetachedStateField=true)/
property name=openjpa.Compatibility
value=IgnoreDetachedStateFieldForProxySerialization=true/
The problem with the other JPA providers was the following scenario:
1.) load from db
2.) change
3.) serialize (store in JSF @ViewScoped and wait for 2nd request)
4.) deserialize
5.) change in the JSF applyValues phase
6.) merge in a JSF action
if you could change 5 and 6 then the other providers work as well. Too bad that
doesn't fit the JSF workflow!
OpenJPA accomplishes this by _still_ using a StateManager, even if the entity
is detached.
In EclipseLink this didn't work at all.
In Hibernate it will work if you do _not_ use any Lazy Loading. Maybe that's
the reason why HIbernate in the default modeeven ignores FetchType.LAZY in the
top layer of your entity and always does eager fetching.
LieGrue,
strub
PS: I'm using build-time-enhancement with the openjpa-maven-plugin
- Original Message -
From: Andrew Hastie and...@ahastie.net
To: users@openjpa.apache.org
Cc:
Sent: Wednesday, May 2, 2012 8:56 PM
Subject: Re: OpenJPA vs EclipseLink
For information, OpenJPA it is also embedded with IBM WebSphere.
On 02/05/12 19:25, José Luis Cetina wrote:
Hi im newbie in OpenJPA i know OpenJPA is an implementation as EclipseLink,
i always used EclipseLink, now im moving from Glassfish to TomEE and i see
openjpa is embeded with TomEE, i read the OpenJPA manual and i like the
innovations in openjpa, but i just want to know the
advantages/disadvantages of openjpa, or a little comparative with openjpa
vs eclipselink or hibernate, and one more thing about how fast is openjpa
vs others.
