Richard
An EJB client can get a handle to a reference, store it and use it later
(in a differenct session)... a kind of persistent remote reference.
Tony
----
Richard Monson-Haefel wrote:
>
> Good points. I don't want to throw out OO modeling either since that's what I
> do for a living, but maybe we need an EJB extension.
>
> Anyway, one thing that would help is remote references that were specified as
> being persistent. Then entity bean components could hold references to other
> entity beans as part of the persistent state. Obviously this would require
> non-OODB EJB containers to do more work, but it would provide a simpler model
> for the rest of us.
>
> Richard
> BTW - I know Ricard already has smart proxies but i'm talking about supporting
> it in the EJB specification ... I don't care how its manifested.
>
> Chris Raber wrote:
>
> > Richard,
> >
> > I for one am not ready to through out the baby with the bath water yet.
> > Hey we just now finally have a standard to oo modelling (UML), and
> > folks are just starting to grock it.
> >
> > Loosely, my opinion is that one should use an oo model, and wrap it with
> > coarse grained components that interact with the model in a transactional
> > way. The coarse grained components can be SB's or EB's as appropriate.
> >
> > This highlights the area of modelling relationships. Relationships between
> > EB's are by key or remote reference (the two are interchangeable, i.e. you
> > can get one from the other). So how to handle the relationships Inside the
> > coarse grained componts (i.e. within the object graph)? Well if you have
> > and oodb, these can just be object references. If you are OR mapping then
> > you are swizzling between object references and keys (but more transparently
> > than EB's do).
> >
> > It would be nice if we had a single idiom for relationships in both cases
> > (inter
> > and intra component).
> >
> > -Chris.
> >
> > > -----Original Message-----
> > > From: Richard Monson-Haefel [SMTP:[EMAIL PROTECTED]]
> > > Sent: Friday, May 07, 1999 7:15 AM
> > > To: [EMAIL PROTECTED]
> > > Subject: Re: Granularity of EJBObjects
> > >
> > > I have been thinking on and off about these types of problems for over a
> > > year and have listened with great interest to threads like this one.
> > > The following is simply my thoughts on the mater and do not represent a
> > > solution.
> > >
> > > It seems to me that OO design with respect to associations has an
> > > impedance mismatch with EJB. Attempts to model associations are
> > > especially
> > > difficult when those associations have a cardinality with multiplicity
> > > (one-to-many or many-to-many). This is do to the differences between an
> > > object graph and a component graph (a concept I wrote about a few months
> > > ago). Because references to other beans are remote references,
> > > navigating the component graph has serious penalties that are not
> > > experienced with domains models that are manifested in traditional OO
> > > systems. Interestingly enough, this problem is not specific to EJB, but
> > > is also experienced in other distributed object systems like CORBA.
> > >
> > > Is it possible that much of what we know today about OO domain modeling
> > > needs to change to fit the new server-side component model? I'm
> > > beginning to believe that server-side components require a slightly
> > > different design methodology than OO systems. I certainly don't believe
> > > we
> > > need to throw out everything we have learned about OO analysis, design and
> > > development, but I think design and development needs to be modified
> > > for server-side components. An OO design just doesn't map to a
> > > server-side component model.
> > > --
> > > Richard Monson-Haefel
> > > Senior Consultant
> > > BORN Information Services
> > >
> > > Author of Enterprise JavaBeans
> > > Published by O'Reilly & Associates
> > > (Available June 1999)
> > >
> > > ==========================================================================
> > > =
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> > > body
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> >
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>
> --
> Richard Monson-Haefel
> Senior Consultant
> BORN Information Services
>
> Author of Enterprise JavaBeans
> Published by O'Reilly & Associates
> (Available June 1999)
>
> ===========================================================================
> To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
> of the message "signoff EJB-INTEREST". For general help, send email to
> [EMAIL PROTECTED] and include in the body of the message "help".
--
Tony Holderith | Interactive Business Solutions
[EMAIL PROTECTED] | NetCentric Solutions
http://www.interactivebusiness.com | Business Objects
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