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From Reinhard Pötz <reinhard_po...@gmx.net>
Subject RE: Flow Database stuff ( The new FOM? )
Date Mon, 14 Jul 2003 12:22:13 GMT

From: Jeremy Quinn
 
> On Sunday, July 13, 2003, at 10:30 AM, Reinhard Pötz wrote:
> 
> >
> > From: Jeremy Quinn [mailto:jeremy@media.demon.co.uk]
> >
> >> By passing a Bean persisted by Hibernate from the flow 
> layer to the 
> >> view layer, you are implementing SoC by allowing the view layer to 
> >> decide what is relevant for that view. This aspect not being the 
> >> Flow's concern.
> >
> > Only to make it transparent (for me): The flow layer passes e.g. a 
> > user bean with the id 4711 to the view layer. The view layer only 
> > "knows" that it can expect a user bean and has tho show 
> e.g. the name 
> > and the adress and so it doesn't care where the bean comes from 
> > (database, webservice, ...). Do we agree on this?
> 
> I reckon we do

Fine :-)

<snip/>

> > Why do you think it is self-defeating? IIUC the point of lazy 
> > initialization is calling the persistence layer at the time 
> when it is 
> > really needed (when I generate some output). If I pass the bean with
> > sendPageAndWait("myPage", {bean:bean}) I *already know* that I need 
> > this
> > bean
> > - otherwise I wouldn't pass it, wouldn't I?
> 
> OK, yes in this simple case you are right.
> 
> I am too tied up in my head with my current project where I have lots 
> of "one-to-many" and "many-to-many" relationships between composite 
> beans, whereby loading one Bean would conceptually load >10k rows out 
> of my DB.
> 
> Under these circumstances I take advantage of lazy-initialisation and 
> let the view layer decide that it wants to show (eg.) siblings 
> (bean.parent.children) for navigation purposes, or just a few local 
> properties (bean.name, bean.description etc.) for editing.

Thank you. This was the argument I was looking for. Now
lazy-initialization
makes sense to me.

> 
> Additionally, in the case of editing, I tend to copy the editable 
> properties to a temporary JS Properties list to pass to the 
> view layer 
> as I do not wish to be bothered with rolling back any changes if the 
> user cancels halfway through, though this might not be one of my best 
> design decisions ;)

Reinhard 


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