thanks Chris,
just to be sure I understud everything fully (before spending many hours
coding):
- EJB-server applications will always be writting EJB(RMI)-style / the
code-generators of the container/server on which the EJB will be
deployed will generate RMI- or CORBA-proxys-classes (when CORBA is
supported)
- when using CORBA on the server-side i have to write my client using
CORBA as well or can write my code RMI-style and can use (in the near
future) RMI-over-IIOP
any problems with OBV or IIOP-firewall-proxies ?
thanks, sven
Chris Raber wrote:
>
> I'll take a stab at your questions.
>
> > -----Original Message-----
> > From: Sven-Uwe Meyer [SMTP:[EMAIL PROTECTED]]
> > Sent: Wednesday, March 03, 1999 7:50 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: IDL from EJB
> >
> > Chris Raber wrote:
> > >
> > > The EJB CORBA mapping specification describes how this should work.
> > >
> > > It is a question of whether a particular vendor supports it or not.
> > > GemStone/J
> > > for example is built on top of CORBA, so we will be able to support this
> > > eventually. We are not quite there yet. In the interim you can create a
> > > CORBA
> > > object and expose it's IDL to CORBA client, and have the implementation
> > > of that CORBA object simply turn around and invoke on EJB's.
> >
> > I'm in the phase of having to decide if i use RMI or CORBA for my
> > proof-of-concept-prototype (based on Gemstone/J 2.01) and I'm not quite
> > sure if i understand the topic (and problems) fully.
> >
> > - Is this really or problem ? Do i really have to decide now to use RMI
> > or CORBA now.
> >
> As an EJB developer the transport level is transparent. The semantics are
> like
> RMI, but the underlying mechanism might actually be CORBA/IIOP. This is how
> GemStone/J is archictected.
>
> > - would it make sense to use RMI now (easier ?) aand "upgrade" to CORBA
> > later ?
> >
> >From a developers standpoint, it makes no difference. The CORBA
> infrastructure
> provides a richer backbone for EJB assuming a CosTransaction services is
> there.
>
> > - could I write my clients using RMI and use RMI over IIOP later so that
> > i don't have to change my code to use CORBA ?
> >
> You could do this, but you won't have to change code wither way. One defines
> home and remote interfaces and bean implementations to the EJB standard and
> an EJB server gives them life in the context of RMI or CORBA/IIOP. The
> semantics
> of the object distribution to the developer are always RMI'ish.
>
> > - ... or would it be possible (with not too much overhead) to put all
> > RMI/CORBA-specific code in some extra layer/classes so that i only have
> > to replace them later ?
> >
> The only CORBA specific code would be if you have non-EJB clients which are
> CORBA based, talking to EJBs.
>
> > - is (will) there a (automatic) way to use CORBA instead of RMI later
> > (just redeploying on a CORBA-capable EJB-server/container) ?
> >
> Yes. This is true today!
>
> > thanks to anybody who takes some time to clarify this topic,
> >
> At your service.
>
> > sven
> > --
> > -----------------------------------------------------------------------
> > Sven-Uwe Meyer
> > Gruner+Jahr Electronic Media Service GmbH tel. : +49-40-370 377 29
> > Am Baumwall 11 fax. : +49-40-370 377 57
> > 20459 Hamburg
> > Germany email : [EMAIL PROTECTED]
> > -----------------------------------------------------------------------
> >
> > ==========================================================================
> > =
> > To unsubscribe, send email to [EMAIL PROTECTED] and include in the
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> > [EMAIL PROTECTED] and include in the body of the message "help".
>
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--
-----------------------------------------------------------------------
Sven-Uwe Meyer
Gruner+Jahr Electronic Media Service GmbH tel. : +49-40-370 377 29
Am Baumwall 11 fax. : +49-40-370 377 57
20459 Hamburg
Germany email : [EMAIL PROTECTED]
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