[grand-rapids-pm-list] Fwd: Model View Presenter

Thu Jul 12 07:06:51 PDT 2007

Meant to send this message to everyone.....What do you guys think?

Carlus

---------- Forwarded message ----------
From: Carlus Henry <carlushenry at sagetech-llc.com>
Date: Jul 12, 2007 10:06 AM
Subject: Re: [grand-rapids-pm-list] Model View Presenter
To: Jason Porritt <jasonmtu at yahoo.com>

Hey bud....

In your work with MVP, does when the presenter delegates to the model, who
owns the transactions when doing commits?  I am thinking that the model
should own the commits....but what happens if the work that needs to be done
is happening across two seperate model calls.  When the second model
operation fails it should roll back the first.  But you are not able to do
this unless the transaction is being controlled at the presenter level,
which just feels awkward.

What have you done?

Thanks
Carlus

On 7/11/07, Jason Porritt <jasonmtu at yahoo.com> wrote:
>
> Thanks for the follow-up, Carlus.  Atomic Object's Presenter First pattern
> is indeed very interesting, and I kind of wish we had jumped into that
> during the MVP discussion but we probably would have run out of time for the
> Perl testing section.  Here are a few other links related to the meeting I
> meant to share with the group at the end:
>
> UI Design Patterns (Martin Fowler)
>     GUI Architectures <http://www.martinfowler.com/eaaDev/uiArchs.html>
>     Inversion of Control Containers and the Dependency Injection pattern<http://www.martinfowler.com/articles/injection.html>
>
> Perl Testing
>     Test::More<http://search.cpan.org/%7Emschwern/Test-Simple-0.70/lib/Test/More.pm%20>
>     Test::MockObject<http://search.cpan.org/%7Echromatic/Test-MockObject-1.08/lib/Test/MockObject.pm>
>
> And to answer one of Carlus' other questions about IoC (Inversion of
> Control) containers for perl I did find two that look interesting:
>     IOC <http://search.cpan.org/%7Estevan/IOC-0.29/lib/IOC.pm>
>     Peco::Container<http://search.cpan.org/%7Erhundt/Peco-1.0/lib/Peco/Container.pm>
>
> My initial impression is that Peco::Container is a bit simpler than IOC.
> I haven't used either of them yet so I don't have much but the documentation
> to base that on.  Neither of them do anything other than IoC, so a fair
> comparison may be between these two and Java's PicoContainer<http://www.picocontainer.org/>instead of Spring which is a full application framework in addition to an
> IoC container.
>
> Thanks,
> Jason Porritt
>
> ----- Original Message ----
> From: Carlus Henry <carlushenry at sagetech-llc.com>
> To: grand-rapids-pm-list at pm.org
> Sent: Thursday, July 5, 2007 8:48:30 AM
> Subject: [grand-rapids-pm-list] Model View Presenter
>
> For those of you that did not come to the last Perl User Group meeting,
> you missed a great presentation which prompted a wonderful discussion on the
> Model-View-Presenter Pattern (MVP).  Primarily being a J2EE developer and
> with many years of experience with the Struts Framework, I am very familiar
> with the Model-View-Controller (MVC).  I was very interested, however, in
> this MVP pattern.  This is mostly due to the thick client application
> development that I have been doing lately.
>
> During the meeting, a lot of questions were raised regarding this pattern,
> and Jason Porrit was very patient with all of us (touche').  After the
> meeting, I decided to do a little more investigation, and found the
> following:
>
> Martin Fowler Retires Model View Presenter Pattern
>
> Yes.  Believe it or not, this pattern has been retired<http://www.martinfowler.com/eaaDev/ModelViewPresenter.html>by Martin Fowler.  Well, I don't know if retired is the correct 'r'-word.
> Maybe it should say 'R'efactored instead.  He has split up the pattern into
> the Supervising Controller<http://www.martinfowler.com/eaaDev/SupervisingPresenter.html>and the Passive
> View <http://www.martinfowler.com/eaaDev/PassiveScreen.html>.  After
> reading both of the patterns, they sound very similar in detail and in
> practice.  In the Passive View you put all of the widget population logic
> into the Presenter.  All logic is pushed on the Presenter including the
> population of text fields or any other widgets available on the View.  In
> the Supervising Controller, you push most of the logic onto the Presenter,
> but leave some of the logic of populating widgets in the View.  Martin
> states:
>
> "...the essence of a good *Supervising Controller* is to do as little as
> possible. Let the view handle as much as possible and only step in when
> there's more complex logic involved."
>
> Atomic Object Presenter First
> On a related note, Atomic Object <http://atomicobject.com/> also has their
> own variation of the MVP Design pattern called Presenter First (PF).  After
> reading an article from Better Software magazine (referenced from their PF
> resources <http://atomicobject.com/pages/Presenter+First>), I find this
> design pattern very attractive as well.  What most attracts me is the
> concept of linking different PF triads in order to orchestrate behavior and
> a process.  Please refer tot he Better Software article for more information
> on this.
>
> Overall, I owe a big thanks to Jason Porrit for inspiring me to learn more
> about this design pattern.  I look forward to hearing him present in the
> future.
> --
> Carlus Henry
> SageTech L.L.C.
> www.sagetech-llc.com | http://jdcarlflip.blogspot.com/
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-- 
Carlus Henry
SageTech L.L.C.
www.sagetech-llc.com | http://jdcarlflip.blogspot.com/

-- 
Carlus Henry
SageTech L.L.C.
www.sagetech-llc.com | http://jdcarlflip.blogspot.com/
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