Well, they've mentioned something called "Bimodal data access" in their
Design Patterns. Database is read from the client side only for sake of
performance, and ONLY in cases where consistency of data is not of importance.
Of course, I don't have any experience, so I can't comment on whether it
really makes sense. As for me, I don't like it that much. I prefer to have
low-performance data that is consistent.
Erwin
At 11:08 PM 4/29/01 +1000, you wrote:
>If it really does that, than - IMHO - the example is garbage.
>In my understanding the EJB server should take care of all
>transactions, security, lala - reading the stuff from the
>web tier is essentially a "fat client" - ugly.
>Comments anyone?
>
>R.
>-----Original Message-----
>From: Erwin [mailto:[EMAIL PROTECTED]]
>Sent: Sunday, April 29, 2001 22:50
>To: [EMAIL PROTECTED]
>Subject: Fwd: value objects
>
>
>Hi again guys,
>
>I found the answer to my own question
>
>I had misunderstood the source code.
>
> >2) The CatalogEJB in PetStore source code returns a ListChunk type, which
> >contains the entire list of objects.
>
>Well, it doesn't return it from the EJB tier - it reads the database from
>the web-tier itself, and creates the value object. So no need to serialize
>anything here, because it doesn't go over the network.
>
>I guess I'll have to chop up my value objects into smaller objects. *sigh*
>
>thanks anyway
>
>Erwin
>
> >Date: Sun, 29 Apr 2001 17:53:27 +0530
> >To: [EMAIL PROTECTED]
> >From: Erwin <[EMAIL PROTECTED]>
> >Subject: value objects
> >
> >Hi guys,
> >
> >I was reading through Design patterns for the Pet Store.
> >
> >They say 2 contradictory things:
> >
> >1) Value objects are unsuitable for Large objects. When you need to send
> >back a large list, it is better to model each *row* as a value object
> >instead of the entire list.
> >
> >2) The CatalogEJB in PetStore source code returns a ListChunk type, which
> >contains the entire list of objects.
> >
> >The explanation for the first was something like: Serializing large
> >objects takes so much time that it overshadows the savings of network
>latency.
> >
> >I really don't know what to do now. Should I proceed with large objects,
> >or should i chop them up?
> >Any advice or suggestions will be truly appreciated
> >Thanks
> >
> >-Erwin
>
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