Personally I think this issue about passing partial object graphs is
irrelevant in some ways. Two issues come to mind:
First not all CORBA implementations of EJB support Java serializable types,
most allow standard CORBA structs but not PBV as we are used to in Java RMI.
In these cases you have to develop your PBV objects to be very simple with
public attributes so that it can double as CORBA structs if necessary.
Second, PBV should be done with care. I have outlined some ground rules for
PBV in a paper I submitted to the EJB workshop
(http://www.inprise.com/events/ejbdesign/submissions/Pass-by-Value.html).
Generally, PBV is a bad idea in Component Transaction Monitor (CTM)
applications because of problems with object equivalence and performance.
You can use PBV as described in my paper, but anything more complicated will
cause problems in the long run.
You can't design EJB solutions like business object systems because you are
dealing with solutions that span address spaces. Your approach needs to be
completely different stressing the use of session beans to manage workflow
and act as an interface to your clients (applets, servlets, etc.), and
limited use of entity beans on the client. Entity bean should focus on
consistent and safe access to related data.
There is a lot more to this than meets the eye and there is no way I can
cover it all in an e-mail - a book maybe.
Thanks,
Richard
-----Original Message-----
From: Eric R. Williams
To: [EMAIL PROTECTED]
Sent: 2/22/99 8:47 AM
Subject: Re: Question regarding Session and Entity Beans
[EMAIL PROTECTED] wrote:
>
> <...>
>
> None of these issues are explicitly covered in the EJB 1.0
specification. I
> view this as a major hurdle for EJB to overcome before it hits the
mainstream.
> I don't like the idea of shops building their own marshaling code,
since that is
> non-portable and violates the rapid application development EJB value
> proposition.
Why would you have to build your own marshalling code? EJB fully
handles RMI parameter types, which includes Serializable objects.
It seems to me that data-transfer between the client and server
should primarily take the form of Serializable objects.
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