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Message-ID: <418E8A59.9050803@mobilebox.pl>
Date: Sun, 07 Nov 2004 21:49:29 +0100
From: Leszek Gawron <lgawron@mobilebox.pl>
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To: dev@cocoon.apache.org
Subject: Re: [OT]DTO Pattern (was  Re: [RT] Attribute Rendering and CForms
 Convertors)
References: <5E091A68F794974CAF431CA31F5AF2CC11E99F@server.bizzdesign.nl>
 <4187D02F.9090209@nada.kth.se> <418A3C62.7020800@apache.org>
 <418B4E93.5050808@nada.kth.se> <418B53C3.9020000@mobilebox.pl>
 <418DF5D1.6060005@gmx.de> <418E4BA0.2000206@mobilebox.pl>
 <418E5A05.6080302@dslextreme.com> <418E7876.8040409@mobilebox.pl>
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Ralph Goers wrote:
> Leszek Gawron wrote:
> 
>> There is one big difference when using Hibernate(d) model: You do not 
>> have to use DTOs so it's easier to scale the system but harder to 
>> enhance particular views with some specially rendered data.
>>
>> I try to avoid DTO pattern as much as I can.
> 
> 
> This is completely off topic.
> My guess is that your system has a presentation tier and a database?  We 
> want to have all our business logic in a separate tier from 
> presentation. In our case this happens to be an EJB container.  Thus our 
> database structure, our entity model and what is actually returned to 
> the presentation tier might be very different things. I don't see how 
> you can do that if you are going straight to Hibernate.
Data passed from view mostly consists of hibernate entities (and a bunch 
of configuration variables but that doesn't count). Almost whole system are:
- CRUD views (create/update/delete) handled by CForms
- entity listings that allow proper navigation

The remaining 10% was of course most interesing to implement. There are 
some cases (i.e. reporting, complex data manipulation) when a special 
structure is being passed to the view that aggregates a lot of 
information from different entities. That probably is something very 
close to your DTO but as it gathers very different data I wouldn't call 
them DTO (Still I might have a bad idea about what really DTO is).

When using O/R tool and having a model that defines a lot of lazy loaded 
depencidencies you rarely need a custom DTO for the view.

-- 
Leszek Gawron                                      lgawron@mobilebox.pl
Project Manager                                    MobileBox sp. z o.o.
+48 (61) 855 06 67                              http://www.mobilebox.pl
mobile: +48 (501) 720 812                       fax: +48 (61) 853 29 65

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