Hi Quintin ,
Thanks for the interest.
I am experimenting (currently not under pressure) at the roots of a new
persistence gateway that I am writing for a broader application, which
leaves the first question open to a flat 'no'.
I guess I have already discounted the feasibility over night, but still
have a scenario that opens a new topic.
First, I am using OpenEJB as an embedded entity cache (on the latest
Derby - which is performing brilliantly I have to say!), and also as a
local EJB gateway.
Without going into the nitty gritty, I basically (understatement) have a
JBoss (JB) cluster that can be joined by further servers at any time
(servers can also go off-line).
Each server in the cluster brings in it's own separate, yet identical,
persistence unit (PU) and announces the fact to all clients through
messaging.
1. JB1 - PU1 - Initial
2. Clients fire up...
3. JB2 - PU2 - Joins JB1 in a cluster 10 minutes later for example.
4. JBn -PUn.... etc.
JB1 to JBn drop in and deploy each others PUs so that EJBs on both JBs
can service calls to any PU throughout the cluster.
So, now to the client. The client has started and created a
configuration for OpenEJB based upon the current JB cluster (initially PU1).
The client creates a PU identical to the PU1 on the cluster - this is
used locally to cache entities retrieved from the JB cluster.
3. <-- Ten minutes later PUn comes on-line and the client obtains a
notification message .
The client cannot be restarted as it may be processing information to
and from the PU1 cache, but it should now have to opportunity to
redirect relevant data to and from a new local PUn cache context.
The first option I pondered over was to run a new OpenEJB process
(either local remote or embedded) with the new local PU cache and EJB
application to service each PU on the cluster. This led me to my initial
question - 'run multiple instances of OpenEJB in the same jvm'
However, I think that a better more lightweight option is to have one
OpenEJB embedded instance that provides access to EJBs that in turn
obtain EntityManagers from EntityManagerFactories bound to the
corresponding PU cache determined by the call context. I would replace
the @PersistenceUnit on EJBs with an @EJB helper to lookup and provide
the EMs to the EJBs.
What I would really like to do is sew in a new named persistence unit
dynamically at any time 'after' start up of OpenEJB - including the
dynamic DataSources.
This leads to the new question - Is it possible to directly access
OpenEJB (Assembler assembler =
SystemInstance.get().getComponent(Assembler.class);) and create or
define a new PU on the fly? - Using appInfo.persistenceUnits.add() for
example. Is that safe?
Best regards,
Andy.
Quintin Beukes schrieb:
What are you trying to achieve?
Quintin Beukes
On Wed, Oct 7, 2009 at 4:45 PM, Andy Gumbrecht
<[email protected]> wrote:
Hi all,
Is it possible to run multiple instances of OpenEJB in the same jvm?
Something like this...
JVM{
Session1{
OpenEJB1{Persistence-unit(bob - points to DB 1)}
}
Session2{
OpenEJB2{Persistence-unit(bob - but this points to DB 2)}
}
}
Thanks in advance,
--
------------------------------------------------------------------------
*Andy Gumbrecht*
Software Developer
Orpro Vision GmbH
Hefehof 8, 31785, Hameln
Tel +49 (0) 5151 809 44 21
Cell +49 (0) 174 1800 381
Email [email protected]
Web www.orprovision.com
Orpro Vision GmbH
Sitz der Gesellschaft: 31785, Hameln
USt-Id-Nr: DE264453214
Amtsgericht Hannover HRB204336
Geschaeftsfuehrer: Roberto Gatti
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--
------------------------------------------------------------------------
*Andy Gumbrecht*
Software Developer
Orpro Vision GmbH
Hefehof 8, 31785, Hameln
Tel +49 (0) 5151 809 44 21
Cell +49 (0) 174 1800 381
Email [email protected]
Web www.orprovision.com
Orpro Vision GmbH
Sitz der Gesellschaft: 31785, Hameln
USt-Id-Nr: DE264453214
Amtsgericht Hannover HRB204336
Geschaeftsfuehrer: Roberto Gatti
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diese Mail. Das unerlaubte Kopieren, jegliche anderweitige
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nicht gestattet.
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information. If you are not the intended recipient (or have
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