What does view mean?

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Peter Svensson

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Aug 21, 2008, 6:41:58 AM8/21/08
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I'm rolling around ideas in my head here, and I think one of my problems is the generic rules we're looking for , because I'm always falling down to concrete problems in the browser-server domain.
The it struck me that i don't really understand the TSA/SOFEA ideas in any other light than that. Granted. This might seem to be a daft questions, but if we agree on one of the basic premises being that the server should not implement any view-related logic, excercise any server-side templating of canned views, et.c., then I have the following questions;

If the client is another (generic) system with no other property than that it receives data, what does View mean in this context?


Cheers,
PS

Ganesh and Sashi Prasad

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Aug 21, 2008, 8:00:45 AM8/21/08
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Peter,

The fundamental questions are always the hardest :-).

Let me try to see if the SOFEA definition is rigorous enough to answer this, since I'm most familiar with that.

Well, in the SOFEA world, we don't rule out a server component (the download server) serving up templates on demand as long as the client application is the one filling up the template with data. The restriction on the server side is against "Presentation Flow" and against mediating service requests. So any merging of data (from a service invocation) with templates should only be done on the client side. If the download server merges data with templates, then it means it is acting as an intermediary between the client and the business logic, which is forbidden.

The SOFEA definition for Presentation goes beyond "visual" components. Even a voice interface is part of Presentation. The "view" here pertains to how the application *appears* to flow from one "screen" to the next. The appearance could be achieved in a number of ways. Actual pages could be replaced, or some JavaScript magic could be hiding and revealing DIVs. Or in the case of a rich client, components could be appearing and disappearing in arbitrary ways. So it's not possible to define Presentation Flow precisely other than as an *illusion* of movement or change.

I don't know if this makes things any clearer.

We could also define the View by elimination, I suppose, again in the context of SOFEA.

One part of the system deals with getting the application onto the client device so that it can run. This is the Application Download bit.
Another part of the system is the actual business logic which only has to do with non-visual data. Pass data in, get data out. This we called Data Interchange.
What's left in an application is Presentation Flow. The application is already running on the client and data is being transmitted to and from services. We have forbidden the use of server-side resources for any other purpose. So all remaining functions must now be done on the client. Whatever happens here is the View.

Does that explain it a little better?

Regards,
Ganesh

2008/8/21 Peter Svensson <psve...@gmail.com>

Peter Svensson

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Aug 21, 2008, 8:21:49 AM8/21/08
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Well yes indeed.

I think that my general confusion came with trying to define what View was when there was no presentation, since you wrote before that it need not be a browser the client. I tried to envision views in a headless server in the middle of a network that requests data from another. Where's the view there?

But even if we're not restricting ourselves to just browsers, the client must at least be some kind of presentation device, since else View loses its meaning.

Cheers,
PS

Ganesh and Sashi Prasad

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Aug 21, 2008, 10:29:50 AM8/21/08
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Absolutely. There has to be a Presentation layer, otherwise it's not SOFEA, it's just SOA ;-).
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