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From Joerg Heinicke <>
Subject Re: [RT] Attribute Rendering and CForms Convertors
Date Wed, 10 Nov 2004 09:17:27 GMT
On 09.11.2004 16:07, Reinhard Poetz wrote:

>> I'm interested in it because I write my diploma thesis exactly about 
>> this topic at the moment. I come to the conclusion that MVC more or 
>> less can not work - and especially templates! I switched back to a 
>> similar solution to the mentioned Lofex one (i.e. application-driven) 
>> but with a more sophisticated model than just the data of the 
>> application as it was for Lofex. It's build on the pattern 
>> "Presentation Abstraction Control" I read first about in German 
>> Javamagazin 09/2004.
> I (tried to) read this article. AFAIU interesting stuff but a little too 
> academic IMHO.

But it's from his practical experience :-)

> Then I followed the reference to 
> which 
> is easier to understand.

This article is not that scientifical ("Let's define darkness as new 
industry standard."). And it contains some statements I definitely can 
not agree with ("Gripe #2. Different views into the same object"). And 
it's not about PAC, but just visual proxy.

> The main adavantage of this visual-proxy pattern (which is based upon 
> the presentation abstraction control pattern) is, that the complete 
> information that belongs to a certain object is encapsulated by it. If 
> you need another property on your object, you simply change one object 
> and every other object using it doesn't have to be changed.

Exactly. MVC with getters for data on the object break 
object-orientation as you make the data or its implementation public. 
Instead of asking for the data you ask for the proxy, an object that 
allows you to present or edit the data. The data itself and its 
implementation is encapsulated into this object.

> As you pointed out, cForms requires you to change on many places in the 
> case you want to add another property to your object. Is this the price 
> to pay, if you want to seperate presentation from data definition to get 
> the possibility to support more then one view?
> Can you describe the result of your research in your thesis?

The VP article is about having just one view (see gripe #2 mentioned 
above). I can not agree with it and I want to use VP in web 
applications. My thesis will be about having the advantages of PAC/VP 
and Cocoon.


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