Chris,
Thanks for the response. I understand many of the items in your email. The
later portion (client caching / density / pass value) is the part I was
looking to understand in more detail. We received a demo copy of Gemstone I
am going to install soon. In your opinion, what differentiates your product
over your competition? Realistically, who do you view as your competition?
Thanks for the information!
-----Original Message-----
From: Chris Raber [mailto:[EMAIL PROTECTED]]
Sent: Monday, May 01, 2000 10:15 AM
To: [EMAIL PROTECTED]
Subject: Re: accessing the middle tier
David,
First of all, EJB is based on the RMI style of defining remote interfaces.
This means that your business interfaces in EJB are defined as Java
interfaces. Secondly, RMI is an interface, not an implementation. Various
EJB servers provide implementations of RMI. Some use JRMP (the
implementation bundled with the JDK), some use RMI/IIOP (i.e. CORBA) and
some use "proprietary" RMI implementations.
It should be noted that the EJB specification has portabilty as a primary
goal, but not interoperability. I suspect this will change in a future
release, but it is not part of current specification wrk to my knowledge.
None the less, my personal bias is to use an EJB server based on IIOP, which
opens up the possibility of wider interoperabiolity (e.g. cross language and
cross platforms).
As for as handling "a client that is more complex", I don't thing RMI or
CORBA differ much here. Either way you must address this issues of pass by
value to the client in an efficient manner. If you read through the archives
you'll see this is a complex issue, and that there are Lots of opinions. One
thing "good" about CORBA in this sense is that it forces you to carve state
out of your objects in order to get that state over to your client. This is
somewhat of a pain, but does not seduce you into thinking that copying large
object graphs to the client or using fine grained remote interfaces is free.
Regards,
-Chris.
PS: The IIOP issue is a potential holy war issue given that one of the more
prevelant EJB servers is not IIOP based.
PPS: We cover a significant amount of this territory in the Developer's
Guide that is freely avaialble on our WEB site: www.gemstone.com. If you
just want to read the guiding design principles, see:
http://www.javasuccess.com/design_wp.html. By value semantics is oneof many
topics covered.
> -----Original Message-----
> From: Hussman, David [SMTP:[EMAIL PROTECTED]]
> Sent: Friday, April 28, 2000 5:28 PM
> To: [EMAIL PROTECTED]
> Subject: accessing the middle tier
>
> Our group is about to embark on a middle tier project. While trying to get
> our mind around our client, we have decided to pursue accessing the middle
> tier
> from both the web tier as well as directly from the client (RMI-IIOP or
> CORBA-IIOP). The J2EE architecture documentation does not touch on the
> later
> of the two, but we believe that it would be helpful when the client is
> more
> complex. We are looking for any comments, suggestions, or success and /or
> horror stories.
>
> David Hussman
> Retail.com
> [EMAIL PROTECTED]
> 612-395-8714
>
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