You are viewing a plain text version of this content. The canonical link for it is here.
Posted to user@geronimo.apache.org by "Hans J. Prueller" <ha...@gmx.net> on 2007/01/25 07:15:05 UTC
other appserver/ejb2.1 to geronimo 2.0 migration strategy?
hi together,
I have been working with the JOnAS Java 2 EE application server for about 5
years now, meanwhile
I have several projects, one of them is rather big already, it contains
about 60-70 EJB's, two thirds
of them are CMP/CMR'ed entity beans, the rest stateless session beans.
I am thinking about migrating these projects to Geronimo for some months
now, and I decided to
wait for the first Java EE 5 release of Geronimo (Geronimo 2) - as it will
be released within the
near future I would be interested in which migration strategies you could
suggest?
I think the most problematic part will be to migrate the ca. 50 CMP entity
beans, there are a lot
of EJB-QL finders and all of those beans are inter-related with CMR.
Currently I'm thinking of doing a "soft" migration, i.e. migrating 1 by 1 of
those EB's within the
currenty architecture from CMP to hibernate, and after that performing the
move to Geronimo (which will
mean that then only the session beans will have to be migrated which should
be less problematic).
what do you think about that?
Anybody already migrated large CMP/CMR apps to Geronimo?
regards,
Hans
===========================
virtually hanzz...
<http://hanzz.zapto.org/> http://hanzz.zapto.org (personal)
<http://www.cse.dmu.ac.uk/~hansp> http://www.cse.dmu.ac.uk/~hansp
(research)
Re: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
Posted by Lasantha Ranaweera <la...@opensource.lk>.
Hi Hans,
I know it is not easy to migrate this kind of business application like
small sample application given below. We would be love to help you to
get going with Geronimo.
This is a small sample with both a CMP and CMRs but it is for J2EE 1.4
and G 1.1.
http://cwiki.apache.org/GMOxDOC11/ejb-sample-application.html
Also you might able to get more information from the Daydarader sample
application because it is fairly big application compared to the sample
given above.
Hope this help you to get starting ;-) .
Thanks,
Lasantha Ranaweera
Hans J. Prueller wrote:
>
> hi together,
>
> I have been working with the JOnAS Java 2 EE application server for
> about 5 years now, meanwhile
>
> I have several projects, one of them is rather big already, it
> contains about 60-70 EJB’s, two thirds
>
> of them are CMP/CMR’ed entity beans, the rest stateless session beans.
>
> I am thinking about migrating these projects to Geronimo for some
> months now, and I decided to
>
> wait for the first Java EE 5 release of Geronimo (Geronimo 2) – as it
> will be released within the
>
> near future I would be interested in which migration strategies you
> could suggest?
>
> I think the most problematic part will be to migrate the ca. 50 CMP
> entity beans, there are a lot
>
> of EJB-QL finders and all of those beans are inter-related with CMR.
>
> Currently I’m thinking of doing a “soft” migration, i.e. migrating 1
> by 1 of those EB’s within the
>
> currenty architecture from CMP to hibernate, and after that performing
> the move to Geronimo (which will
>
> mean that then only the session beans will have to be migrated which
> should be less problematic).
>
> what do you think about that?
>
> Anybody already migrated large CMP/CMR apps to Geronimo?
>
> regards,
>
> Hans
>
> ===========================
> virtually hanzz...
>
> http://hanzz.zapto.org <http://hanzz.zapto.org/> (personal)
> http://www.cse.dmu.ac.uk/~hansp <http://www.cse.dmu.ac.uk/%7Ehansp>
> (research)
>
Re: AW: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
Posted by Dain Sundstrom <da...@iq80.com>.
On Jan 25, 2007, at 1:47 AM, Hans J. Prueller wrote:
> David,
>
>
>
> thank you for your thoughts. You provided good entry points for me.
> I mentioned hibernate specifically because
>
> we already are using hibernate and CMP in parallel within our
> project (as CMP2.x sometimes does not fulfill all needs).
>
>
>
> targeting JPA instead of hibernate specifically is essential –thank
> you for that.
If you can use hibernate in jpa mode, we will be able to support that.
> I also would like to do a one-by-one migration because I am afraid
> if we would migrate the whole project at once,
>
> everything could collapse. Doing smaller steps provides more
> control I think.
That is exactly why I wrote the OpenEjb 3 cmp engine on JPA, so beans
can be migrated one at at time. Migrating a whole app all at once is
just to risky.
> >> However this would mean that you would need to start by
> generating the cmp2 mapping info.
>
>
>
> so this is what should to be contained in the Geronimo deployment
> plan right? are deployment plans required also
>
> in Geronimo2 ? (I think there shouldn’t be any more “vendor”
> specific DDs in Java EE 5). But for compatibility reasons
They won't be required, but vendor-DD less deployment is fully
implemented yet. You can deploy an ejb module without any plans in
2.0-M2, but I don't you can deploy any other module types without a
plan.
> with my EJB2.1 CMP beans I think I won’t come around to provide a
> mapping file at all ;-)
For OpenEJB3 we use a standard JPA entity-mapping.xml file for the
mappings.
> I asked about XDoclet support for Geronimo some months ago, at that
> point in time there was no usable version around.
>
> As Java 2 EE 1.4 requires Java 1.4 I cannot work with annotations
> unless the whole app is migrated, so XDoclet would
>
> be of great help…?
J2ee 1.4 requires java 1.4+. You can run in Java5 if you want.
-dain
AW: AW: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
Posted by "Hans J. Prueller" <ha...@gmx.net>.
>> entity beans with cmr can you still migrate them one by one or do you
>> have to migrate the entire tree of objects?
if I want to migrate one by one, I think I'll have to break up the CMR
relations anyway, thats right.
> I'm not understanding what you are saying here. Geronimo 1.2 (not
> quite released yet) includes jpa support and runs on jdk 1.5 only but
> is (or will be) a j2ee 1.4 app server. In particular the jpa
> annotations all work fine (with openjpa).
yes, but if I want to deploy the existing CMP2.X EB's to Geronimo first,
I'll have to write the full blown mapping file, in this case XDoclet
would ease things like Annotations do with Java5 and JPA.
But to point it out:
I found another .ear application which is rather small sized (ca. 5 CMP
EB's, 2 SLSB's). I will try to use this simple project as an "evaluation
run" about migrating to Geronimo. So if I'd like to start migration of
this app what would you suggest: start right with Geronimo 2.0 or start
with 2.1 - will there be major upgrading issues from G1.2 to G2.0???
I think I'll start to migrate the existing Java EE 1.4 .ear 1:1 to Geronimo
and check out what has to be done and how it works..
regards,
Hans
> -----Ursprüngliche Nachricht-----
> Von: David Jencks [mailto:david_jencks@yahoo.com]
> Gesendet: Donnerstag, 25. Jänner 2007 17:46
> An: user@geronimo.apache.org
> Betreff: Re: AW: other appserver/ejb2.1 to geronimo 2.0 migration
> strategy?
>
>
> On Jan 25, 2007, at 1:47 AM, Hans J. Prueller wrote:
>
> > David,
> >
> >
> >
> > thank you for your thoughts. You provided good entry points for me.
> > I mentioned hibernate specifically because
> >
> > we already are using hibernate and CMP in parallel within our
> > project (as CMP2.x sometimes does not fulfill all needs).
> >
> >
> >
> > targeting JPA instead of hibernate specifically is essential thank
> > you for that.
> >
> >
> >
> > I also would like to do a one-by-one migration because I am afraid
> > if we would migrate the whole project at once,
> >
> > everything could collapse. Doing smaller steps provides more
> > control I think.
>
> That's easy to understand :-). However if you have entity beans with
> cmr can you still migrate them one by one or do you have to migrate
> the entire tree of objects?
> >
> >
> > >> However this would mean that you would need to start by
> > generating the cmp2 mapping info.
> >
> >
> >
> > so this is what should to be contained in the Geronimo deployment
> > plan right? are deployment plans required also
> >
> > in Geronimo2 ? (I think there shouldnt be any more vendor
> > specific DDs in Java EE 5). But for compatibility reasons
> >
> > with my EJB2.1 CMP beans I think I wont come around to provide a
> > mapping file at all ;-)
> I suspect that some plans will still be needed to specify things like
> datasource configuration.
>
> I was wondering if it would be practical to run your app on geronimo
> while it was being converted: I suspect not because you would need to
> have the cmp2 mapping info in a form geronimo could understand, and
> producing that would probably be harder than migrating to jpa directly.
>
> > I asked about XDoclet support for Geronimo some months ago, at that
> > point in time there was no usable version around.
> >
> > As Java 2 EE 1.4 requires Java 1.4 I cannot work with annotations
> > unless the whole app is migrated, so XDoclet would
> >
> > be of great help
?
> I'm not understanding what you are saying here. Geronimo 1.2 (not
> quite released yet) includes jpa support and runs on jdk 1.5 only but
> is (or will be) a j2ee 1.4 app server. In particular the jpa
> annotations all work fine (with openjpa).
>
> thanks
> david jencks
>
> >
> >
> > regards,
> >
> > Hans
> >
> >
> >
> > Von: David Jencks [mailto:david_jencks@yahoo.com]
> > Gesendet: Donnerstag, 25. Jänner 2007 09:24
> > An: user@geronimo.apache.org
> > Betreff: Re: other appserver/ejb2.1 to geronimo 2.0 migration
> > strategy?
> >
> >
> >
> >
> >
> > On Jan 24, 2007, at 10:15 PM, Hans J. Prueller wrote:
> >
> >
> >
> >
> > hi together,
> >
> >
> >
> > I have been working with the JOnAS Java 2 EE application server for
> > about 5 years now, meanwhile
> >
> > I have several projects, one of them is rather big already, it
> > contains about 60-70 EJBs, two thirds
> >
> > of them are CMP/CMRed entity beans, the rest stateless session beans.
> >
> >
> >
> > I am thinking about migrating these projects to Geronimo for some
> > months now, and I decided to
> >
> > wait for the first Java EE 5 release of Geronimo (Geronimo 2) as
> > it will be released within the
> >
> > near future I would be interested in which migration strategies you
> > could suggest?
> >
> >
> >
> > I think the most problematic part will be to migrate the ca. 50 CMP
> > entity beans, there are a lot
> >
> > of EJB-QL finders and all of those beans are inter-related with CMR.
> >
> >
> >
> > Currently Im thinking of doing a soft migration, i.e. migrating
> > 1 by 1 of those EBs within the
> >
> > currenty architecture from CMP to hibernate, and after that
> > performing the move to Geronimo (which will
> >
> > mean that then only the session beans will have to be migrated
> > which should be less problematic).
> >
> >
> >
> > First of all I would target JPA rather than Hibernate specifically.
> >
> >
> >
> > Second, IIUC Dain has reimplemented CMP2 in openejb3 so it is
> > backed by openjpa. This should mean that you could migrate the
> > entity beans one at a time and have coherent caching between the
> > jpa pojos and cmp entity beans. However this would mean that you
> > would need to start by generating the cmp2 mapping info.
> >
> >
> >
> > I converted daytrader from entity beans to jpa very quickly. It
> > was fairly easy because there were already data objects that hold
> > (most of) the same data that the entity beans hold. I just added
> > annotations to the data beans and added the relationships (that had
> > been left out of the data beans for some reason). If your
> > application already has something like a pojo data model layer it
> > would probably be easiest to simply start annotating the data
> > classes and drop the entity beans.
> >
> >
> >
> > Daytrader is not quite a toy app but it's much smaller than your
> > application so my results may not map directly to your situation.
> >
> >
> >
> > thanks
> >
> > david jencks
> >
> >
> >
> >
> >
> >
> > what do you think about that?
> >
> >
> >
> > Anybody already migrated large CMP/CMR apps to Geronimo?
> >
> >
> >
> > regards,
> >
> > Hans
> >
> >
> >
> > ===========================
> > virtually hanzz...
> >
> >
> >
> > http://hanzz.zapto.org (personal)
> > http://www.cse.dmu.ac.uk/~hansp (research)
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
Re: AW: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
Posted by David Jencks <da...@yahoo.com>.
On Jan 25, 2007, at 1:47 AM, Hans J. Prueller wrote:
> David,
>
>
>
> thank you for your thoughts. You provided good entry points for me.
> I mentioned hibernate specifically because
>
> we already are using hibernate and CMP in parallel within our
> project (as CMP2.x sometimes does not fulfill all needs).
>
>
>
> targeting JPA instead of hibernate specifically is essential –thank
> you for that.
>
>
>
> I also would like to do a one-by-one migration because I am afraid
> if we would migrate the whole project at once,
>
> everything could collapse. Doing smaller steps provides more
> control I think.
That's easy to understand :-). However if you have entity beans with
cmr can you still migrate them one by one or do you have to migrate
the entire tree of objects?
>
>
> >> However this would mean that you would need to start by
> generating the cmp2 mapping info.
>
>
>
> so this is what should to be contained in the Geronimo deployment
> plan right? are deployment plans required also
>
> in Geronimo2 ? (I think there shouldn’t be any more “vendor”
> specific DDs in Java EE 5). But for compatibility reasons
>
> with my EJB2.1 CMP beans I think I won’t come around to provide a
> mapping file at all ;-)
I suspect that some plans will still be needed to specify things like
datasource configuration.
I was wondering if it would be practical to run your app on geronimo
while it was being converted: I suspect not because you would need to
have the cmp2 mapping info in a form geronimo could understand, and
producing that would probably be harder than migrating to jpa directly.
> I asked about XDoclet support for Geronimo some months ago, at that
> point in time there was no usable version around.
>
> As Java 2 EE 1.4 requires Java 1.4 I cannot work with annotations
> unless the whole app is migrated, so XDoclet would
>
> be of great help…?
I'm not understanding what you are saying here. Geronimo 1.2 (not
quite released yet) includes jpa support and runs on jdk 1.5 only but
is (or will be) a j2ee 1.4 app server. In particular the jpa
annotations all work fine (with openjpa).
thanks
david jencks
>
>
> regards,
>
> Hans
>
>
>
> Von: David Jencks [mailto:david_jencks@yahoo.com]
> Gesendet: Donnerstag, 25. Jänner 2007 09:24
> An: user@geronimo.apache.org
> Betreff: Re: other appserver/ejb2.1 to geronimo 2.0 migration
> strategy?
>
>
>
>
>
> On Jan 24, 2007, at 10:15 PM, Hans J. Prueller wrote:
>
>
>
>
> hi together,
>
>
>
> I have been working with the JOnAS Java 2 EE application server for
> about 5 years now, meanwhile
>
> I have several projects, one of them is rather big already, it
> contains about 60-70 EJB’s, two thirds
>
> of them are CMP/CMR’ed entity beans, the rest stateless session beans.
>
>
>
> I am thinking about migrating these projects to Geronimo for some
> months now, and I decided to
>
> wait for the first Java EE 5 release of Geronimo (Geronimo 2) – as
> it will be released within the
>
> near future I would be interested in which migration strategies you
> could suggest?
>
>
>
> I think the most problematic part will be to migrate the ca. 50 CMP
> entity beans, there are a lot
>
> of EJB-QL finders and all of those beans are inter-related with CMR.
>
>
>
> Currently I’m thinking of doing a “soft” migration, i.e. migrating
> 1 by 1 of those EB’s within the
>
> currenty architecture from CMP to hibernate, and after that
> performing the move to Geronimo (which will
>
> mean that then only the session beans will have to be migrated
> which should be less problematic).
>
>
>
> First of all I would target JPA rather than Hibernate specifically.
>
>
>
> Second, IIUC Dain has reimplemented CMP2 in openejb3 so it is
> backed by openjpa. This should mean that you could migrate the
> entity beans one at a time and have coherent caching between the
> jpa pojos and cmp entity beans. However this would mean that you
> would need to start by generating the cmp2 mapping info.
>
>
>
> I converted daytrader from entity beans to jpa very quickly. It
> was fairly easy because there were already data objects that hold
> (most of) the same data that the entity beans hold. I just added
> annotations to the data beans and added the relationships (that had
> been left out of the data beans for some reason). If your
> application already has something like a pojo data model layer it
> would probably be easiest to simply start annotating the data
> classes and drop the entity beans.
>
>
>
> Daytrader is not quite a toy app but it's much smaller than your
> application so my results may not map directly to your situation.
>
>
>
> thanks
>
> david jencks
>
>
>
>
>
>
> what do you think about that?
>
>
>
> Anybody already migrated large CMP/CMR apps to Geronimo?
>
>
>
> regards,
>
> Hans
>
>
>
> ===========================
> virtually hanzz...
>
>
>
> http://hanzz.zapto.org (personal)
> http://www.cse.dmu.ac.uk/~hansp (research)
>
>
>
>
>
>
>
>
>
>
>
>
>
AW: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
Posted by "Hans J. Prueller" <ha...@gmx.net>.
David,
thank you for your thoughts. You provided good entry points for me. I
mentioned hibernate specifically because
we already are using hibernate and CMP in parallel within our project (as
CMP2.x sometimes does not fulfill all needs).
targeting JPA instead of hibernate specifically is essential thank you for
that.
I also would like to do a one-by-one migration because I am afraid if we
would migrate the whole project at once,
everything could collapse. Doing smaller steps provides more control I
think.
>> However this would mean that you would need to start by generating the
cmp2 mapping info.
so this is what should to be contained in the Geronimo deployment plan
right? are deployment plans required also
in Geronimo2 ? (I think there shouldnt be any more vendor specific DDs in
Java EE 5). But for compatibility reasons
with my EJB2.1 CMP beans I think I wont come around to provide a mapping
file at all ;-)
I asked about XDoclet support for Geronimo some months ago, at that point in
time there was no usable version around.
As Java 2 EE 1.4 requires Java 1.4 I cannot work with annotations unless the
whole app is migrated, so XDoclet would
be of great help
?
regards,
Hans
_____
Von: David Jencks [mailto:david_jencks@yahoo.com]
Gesendet: Donnerstag, 25. Jänner 2007 09:24
An: user@geronimo.apache.org
Betreff: Re: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
On Jan 24, 2007, at 10:15 PM, Hans J. Prueller wrote:
hi together,
I have been working with the JOnAS Java 2 EE application server for about 5
years now, meanwhile
I have several projects, one of them is rather big already, it contains
about 60-70 EJBs, two thirds
of them are CMP/CMRed entity beans, the rest stateless session beans.
I am thinking about migrating these projects to Geronimo for some months
now, and I decided to
wait for the first Java EE 5 release of Geronimo (Geronimo 2) as it will
be released within the
near future I would be interested in which migration strategies you could
suggest?
I think the most problematic part will be to migrate the ca. 50 CMP entity
beans, there are a lot
of EJB-QL finders and all of those beans are inter-related with CMR.
Currently Im thinking of doing a soft migration, i.e. migrating 1 by 1 of
those EBs within the
currenty architecture from CMP to hibernate, and after that performing the
move to Geronimo (which will
mean that then only the session beans will have to be migrated which should
be less problematic).
First of all I would target JPA rather than Hibernate specifically.
Second, IIUC Dain has reimplemented CMP2 in openejb3 so it is backed by
openjpa. This should mean that you could migrate the entity beans one at a
time and have coherent caching between the jpa pojos and cmp entity beans.
However this would mean that you would need to start by generating the cmp2
mapping info.
I converted daytrader from entity beans to jpa very quickly. It was fairly
easy because there were already data objects that hold (most of) the same
data that the entity beans hold. I just added annotations to the data beans
and added the relationships (that had been left out of the data beans for
some reason). If your application already has something like a pojo data
model layer it would probably be easiest to simply start annotating the data
classes and drop the entity beans.
Daytrader is not quite a toy app but it's much smaller than your application
so my results may not map directly to your situation.
thanks
david jencks
what do you think about that?
Anybody already migrated large CMP/CMR apps to Geronimo?
regards,
Hans
===========================
virtually hanzz...
<http://hanzz.zapto.org/> http://hanzz.zapto.org (personal)
<http://www.cse.dmu.ac.uk/~hansp> http://www.cse.dmu.ac.uk/~hansp
(research)
Re: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
Posted by David Jencks <da...@yahoo.com>.
On Jan 24, 2007, at 10:15 PM, Hans J. Prueller wrote:
> hi together,
>
>
>
> I have been working with the JOnAS Java 2 EE application server for
> about 5 years now, meanwhile
>
> I have several projects, one of them is rather big already, it
> contains about 60-70 EJB’s, two thirds
>
> of them are CMP/CMR’ed entity beans, the rest stateless session beans.
>
>
>
> I am thinking about migrating these projects to Geronimo for some
> months now, and I decided to
>
> wait for the first Java EE 5 release of Geronimo (Geronimo 2) – as
> it will be released within the
>
> near future I would be interested in which migration strategies you
> could suggest?
>
>
>
> I think the most problematic part will be to migrate the ca. 50 CMP
> entity beans, there are a lot
>
> of EJB-QL finders and all of those beans are inter-related with CMR.
>
>
>
> Currently I’m thinking of doing a “soft” migration, i.e. migrating
> 1 by 1 of those EB’s within the
>
> currenty architecture from CMP to hibernate, and after that
> performing the move to Geronimo (which will
>
> mean that then only the session beans will have to be migrated
> which should be less problematic).
First of all I would target JPA rather than Hibernate specifically.
Second, IIUC Dain has reimplemented CMP2 in openejb3 so it is backed
by openjpa. This should mean that you could migrate the entity beans
one at a time and have coherent caching between the jpa pojos and cmp
entity beans. However this would mean that you would need to start
by generating the cmp2 mapping info.
I converted daytrader from entity beans to jpa very quickly. It was
fairly easy because there were already data objects that hold (most
of) the same data that the entity beans hold. I just added
annotations to the data beans and added the relationships (that had
been left out of the data beans for some reason). If your
application already has something like a pojo data model layer it
would probably be easiest to simply start annotating the data classes
and drop the entity beans.
Daytrader is not quite a toy app but it's much smaller than your
application so my results may not map directly to your situation.
thanks
david jencks
>
>
> what do you think about that?
>
>
>
> Anybody already migrated large CMP/CMR apps to Geronimo?
>
>
>
> regards,
>
> Hans
>
>
>
> ===========================
> virtually hanzz...
>
>
>
> http://hanzz.zapto.org (personal)
> http://www.cse.dmu.ac.uk/~hansp (research)
>
>
>
>
>
>
>
>
AW: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
Posted by "Ueberbach, Michael" <mi...@dbh.de>.
Hallo Hans,
ich antworte hier mal direkt auf Deutsch, da ich annehme, dass es verstanden wird (jedenfalls besser als mein Englisch).
Ich sehe eine gewisse Ähnlichkeit zu der Situation, in der wir uns hier befinden. Wir haben mehrere produktive Anwendungen
laufen (einerseits auf dem WeblogicServer von BEA, andererseits auf JBoss), die in der Größenordnung dem von Dir beschriebenen
Szenario entsprechen (z.T. mehr als 110 Entitäten (CMP) mit annähernd 100 Relationen (CMR)).
Seit einiger Zeit beschäftige ich mich (mehr privat) mit der Frage einer Portierung auf Geronimo, wobei allerdings einige Punkte vielleicht
doch einen Unterschied zu Deiner Fragestellung ausmachen. Wir haben uns (wie wahrscheinlich die meisten) den Umgang mit dem etwas
schwerfälligen EJB 2.0 Standard (Interfaces etc.) durch Einsatz eines Generierungssystems erleichtert, das auf Basis von XDoclet,
XSLT-Transformationen und eigenen kleineren Werkzeugen die Erzeugung eines Programmrahmens aus einem in einer Datenbank hinterlegten
Modell gestattet. Das gestattet die relativ leichte Erzeugung aller notwendigen Klassen inklusive von Datentransferobjekten (value objects)
quasi auf Knopfdruck. Mir scheint nach meinen bisherigen Einsichten eine Übertragung eines solchen Vorgehens auf Geronimo durchaus
möglich. (Hinzu kommt nur die Notwendigeit einen Deployment Plan für Geronimo zu erzeugen, was XDoclet nach meiner Kenntnis zur Zeit
noch nicht bietet (?).
Es hat sich hier nur ein einziger Haken gezeigt: Sowohl beim BEA-Server als auch beim JBoss verwenden wir das Konzept der Erzeugung
von Abfragen zur Laufzeit (dynamic queries), um uns einen unübersehbaren Wust an statischen Abfragen auf Deskriptorebene zu ersparen.
Leider gibt es ein solches Konzept zur Zeit innerhalb von openEJB resp. tranQL nicht (soweit ich weiss). Andererseits hat unsere
praktische Erfahrung gezeigt, dass hinsichtlich Performanz Abfragen via JDBC (jdbc for reading) in vielen Fällen sowieso der einzig gangbare
Weg sind. Hier kann man insofern ansetzen, als dass es z.B. möglich ist, via Introspektion aus Datentransferobjekten direkte Abfrage über
JDBC zu erzeugen; meinetwegen um zunächst die Primärschlüssel der gesuchten Entitäten zu ermitteln und dann das Objekt nach Bedarf komplett
nachzuladen (was in etwa der Vorgehensweise der von uns benutzten AppServer entspricht).
So scheint mir auf diesem Weg eine Portierung auf Geronimo möglich zu sein; allerdings verbleibt dies im Rahmen von EJB 2.0.
Eine andere Frage ist, ob ein Wechsel auf EJB 3.0 nicht aus weitergehenden Gründen angeraten ist. Bislang lese ich immer nur, dass
EJB 3.0 die Arbeit des Programmieres erleichtern soll (was natürlich je nach gewählter Vorgehensweise eine relative Frage ist), während
sich das interne Verhalten des AppServers gar nicht wesentlich ändert (?). Das kann ich zur Zeit nicht richtig beurteilen, würde mich aber
sehr interessieren.
Gruss
Michael
-----Ursprüngliche Nachricht-----
Von: Hans J. Prueller [mailto:hans.prueller@gmx.net]
Gesendet: Donnerstag, 25. Januar 2007 07:15
An: user@geronimo.apache.org
Betreff: other appserver/ejb2.1 to geronimo 2.0 migration strategy?
hi together,
I have been working with the JOnAS Java 2 EE application server for about 5 years now, meanwhile
I have several projects, one of them is rather big already, it contains about 60-70 EJB's, two thirds
of them are CMP/CMR'ed entity beans, the rest stateless session beans.
I am thinking about migrating these projects to Geronimo for some months now, and I decided to
wait for the first Java EE 5 release of Geronimo (Geronimo 2) - as it will be released within the
near future I would be interested in which migration strategies you could suggest?
I think the most problematic part will be to migrate the ca. 50 CMP entity beans, there are a lot
of EJB-QL finders and all of those beans are inter-related with CMR.
Currently I'm thinking of doing a "soft" migration, i.e. migrating 1 by 1 of those EB's within the
currenty architecture from CMP to hibernate, and after that performing the move to Geronimo (which will
mean that then only the session beans will have to be migrated which should be less problematic).
what do you think about that?
Anybody already migrated large CMP/CMR apps to Geronimo?
regards,
Hans
===========================
virtually hanzz...
<http://hanzz.zapto.org/> http://hanzz.zapto.org (personal)
<http://www.cse.dmu.ac.uk/~hansp> http://www.cse.dmu.ac.uk/~hansp (research)