David,
I meant to imply my conditions for using CORBA were logically 'ORed'. Your
application hits the last item in my list, so I'd have to concur with your
use of CORBA. My point about 'control over client code' was intended to
mean that since EJB includes transactions and security as part of the server
side framework and a CORBA client would have to do more work to properly
engage transactions and security, I feel it is easier and safer to
distribute EJB client jar files to people and let them go nuts then to do
the same with CORBA. I did not mean to imply it couldn't be done with
either.
Dave
David Brown
Technical Director, Western Operations
GemStone Systems, Inc.
(760)510-2754
[EMAIL PROTECTED]
www.gemstone.com
-----Original Message-----
From: David W Forslund [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, August 30, 2000 10:23 PM
To: [EMAIL PROTECTED]
Subject: Re: need advice on CORBA/EJB interaction
David Brown writes:
> Lou,
> I'm not a CORBA expert either, but my understanding is that the biggest
> hurdle to CORBA-EJB direct integration (i.e. CORBA directly invoking
EJBs)
> is the requirement for CORBA to have pass-by-value. This comes with
CORBA
> 3.0, but I'm not sure which vendors are supporting this yet - we are
> planning to support it in our 5.0 release this year. I have customers
that
> have written CORBA services that call their EJBs. I have other customers
> that have a common domain model that is interfaced by both CORBA and EJBs
> concurrently and transactionally. The former is vender neutral, the
later
> more performant and easier to write.
>
> IMHO -
> When to use CORBA:
> - long term, 'persistent' connections between two servers
> - whenever threads must be spawned to handle requests
asynchronously
> - highly coupled, custom integrations
> - whenever non-Java clients are involved
I'm not sure I agree with these. We use CORBA when we want to use
standard interfaces in a domain. This is in a non-custom integration.
We also use it for transient connections between client and server and
when the service is expected to be re-used by multiple applications. We
also have many people writing clients to a server in which there is no
control over the client code. We also write all of our CORBA code with
Java so that, indeed, non-Java applications can connect. The big CORBA win
is
standard interfaces so that we can build a system from multiple vendor
components on different platforms and different languages. I would like
to be able to use the same interfaces with EJB, but this is harder.
We have an example of this in the openmed project at sourceforge
> When to use EJB:
> - client based, 'transient' connecitons between client and server
> - when service is expected to be re-used by multiple applications
> - when you have less or no control over the client code
>
> Hope this helps.
>
> Dave
>
--
David Forslund Voice:(505) 665-1907
Advanced Computing Laboratory, MSB287 FAX: (505) 665-4939
Los Alamos National Laboratory EMAIL: [EMAIL PROTECTED]
Los Alamos, NM 87545 WWW: http://www.acl.lanl.gov/~dwf
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