see below
> -----Original Message-----
> From: Ian McCallion [SMTP:[EMAIL PROTECTED]]
> Sent: Friday, May 07, 1999 8:19 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Seduction by perceived ease of use,was RE: Granularity
> of EJBObj ects
>
> Javier Deniz wrote:
>
> > I would expect EB being quite close to the object model and the session
> > beans being more closed to the client needs. Different session beans may
> > be used to match different kinds of clients needs. If we need to keep
> > state in the server (stateful session bean), this is even more clear.
>
> The flaw with EBs being close to the object model is that most business
> logic involves traversal of the object graph and this becomes very
> inefficient when each object is an EB. I was delighted to read Chris
> Raber's notes acknowledging this. When the relational guys say it you may
> argue self-interest, but when the OODBMS guys say it you really have to
> start believing it.
>
> I'd only disagree with Chris on one point, He proposed (if I understood
> correctly) that EBs partition the object graph. I don't believe this is
> practical or necessary.
[Chip Wilson]
If EBs do not partition the object graph, then I could have two EBs
resident in memory simultaneously, of different EB classes, and with
different PKs, running in different transaction contexts, but whose
underlying persistent representation is not completely disjoint. The server
will not be able to manage updates to this data, and the EBs will step on
each other's changes.
> It's not practical because different applications might want to make a
> radically different use of the objects (eg order items would be in an
> order
> bean for the purposes of order entry and fulfilment, but would be in a
> stock-type bean for purpose of stock checking).
>
> It's also not necessary, because we gain the benefit of AD-time reuse of
> the objects when constructing EBs, and we get the additional benefit of
> run-time reuse of EBs when we extend the application to enable another
> channel for taking and fulfilling orders.
>
>
> Ian McCallion
> CICS Business Unit
> IBM Hursley
> [EMAIL PROTECTED]
> Tel: ++44-1962-818065
> Fax: ++44-1962-818069
>
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