Meant to send this message to everyone.....What do you guys think?<br><br>Carlus<br><br>---------- Forwarded message ----------<br><span class="gmail_quote">From: <b class="gmail_sendername">Carlus Henry</b> <<a href="mailto:carlushenry@sagetech-llc.com">
carlushenry@sagetech-llc.com</a>><br>Date: Jul 12, 2007 10:06 AM<br>Subject: Re: [grand-rapids-pm-list] Model View Presenter<br>To: Jason Porritt <<a href="mailto:jasonmtu@yahoo.com">jasonmtu@yahoo.com</a>><br><br>
</span>Hey bud....<br><br>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.
<br><br>What have you done?<br><br>Thanks<br><span class="sg">Carlus</span><div><span class="e" id="q_113bac03d6d17139_2"><br><br><div><span class="gmail_quote">On 7/11/07, <b class="gmail_sendername">Jason Porritt</b> <
<a href="mailto:jasonmtu@yahoo.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">jasonmtu@yahoo.com</a>> wrote:
</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">
<div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">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:
<br><br><span style="font-weight: bold;">UI Design Patterns (Martin Fowler)</span><br> <a href="http://www.martinfowler.com/eaaDev/uiArchs.html" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">GUI Architectures
</a><br> <a href="http://www.martinfowler.com/articles/injection.html" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">Inversion of Control Containers and the Dependency Injection pattern</a><br>
<br><span style="font-weight: bold;">Perl
Testing</span><br> <a href="http://search.cpan.org/%7Emschwern/Test-Simple-0.70/lib/Test/More.pm%20" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">Test::More</a><br> <a href="http://search.cpan.org/%7Echromatic/Test-MockObject-1.08/lib/Test/MockObject.pm" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
Test::MockObject</a><br><br>And to answer one of Carlus' other questions about IoC (Inversion of Control) containers for perl I did find two that look interesting:<br> <a href="http://search.cpan.org/%7Estevan/IOC-0.29/lib/IOC.pm" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
IOC</a><br> <a href="http://search.cpan.org/%7Erhundt/Peco-1.0/lib/Peco/Container.pm" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">Peco::Container</a><br><br>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
<a href="http://www.picocontainer.org/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">PicoContainer</a> instead of Spring which
is a full application framework in addition to an IoC container.<br><br>Thanks,<br>Jason Porritt<br><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div><span>
----- Original Message ----<br>From: Carlus Henry <<a href="mailto:carlushenry@sagetech-llc.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">carlushenry@sagetech-llc.com</a>><br>To: <a href="mailto:grand-rapids-pm-list@pm.org" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
grand-rapids-pm-list@pm.org</a><br>Sent: Thursday, July 5, 2007 8:48:30 AM<br>Subject: [grand-rapids-pm-list] Model View Presenter<br><br>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.
<br><br>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:
<br><br><span style="font-weight: bold; text-decoration: underline;">Martin Fowler Retires Model View Presenter Pattern</span><br><br>Yes. Believe it or not, this <a rel="nofollow" href="http://www.martinfowler.com/eaaDev/ModelViewPresenter.html" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
pattern has been retired</a>
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 <a rel="nofollow" href="http://www.martinfowler.com/eaaDev/SupervisingPresenter.html" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
Supervising Controller</a> and the <a rel="nofollow" href="http://www.martinfowler.com/eaaDev/PassiveScreen.html" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">Passive View</a>. 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:
<br><br>"...the essence of a good <i>Supervising Controller</i> 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."<br><br><span style="font-weight: bold; text-decoration: underline;">Atomic Object Presenter First</span><br>On a related note, <a rel="nofollow" href="http://atomicobject.com/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
Atomic Object</a> 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 <a rel="nofollow" href="http://atomicobject.com/pages/Presenter+First" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
PF resources</a>), 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.
<br><br>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.<br></span></div><span>-- <br>Carlus Henry<br>SageTech
L.L.C.<br><a rel="nofollow" href="http://www.sagetech-llc.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
www.sagetech-llc.com</a> | <a rel="nofollow" href="http://jdcarlflip.blogspot.com/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
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</a><br></blockquote></div><br><br clear="all"><br>-- <br>Carlus Henry<br>SageTech L.L.C.<br><a href="http://www.sagetech-llc.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">www.sagetech-llc.com
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</span></div><br clear="all"><br>-- <br>Carlus Henry<br>SageTech L.L.C.<br><a href="http://www.sagetech-llc.com">www.sagetech-llc.com</a> | <a href="http://jdcarlflip.blogspot.com/">http://jdcarlflip.blogspot.com/</a>