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mvc, VO, and tier leakage antipattern

Jeff Horan
Ranch Hand

Joined: Apr 03, 2003
Posts: 37
I've read that you're not to by-pass the view and model tiers without using the controller, however, many examples in books have their jsp use bean:write tags to directly read from a VO. So, what's the scoop? Do I duplicate read only text in the actionform or is the VO considered neutral territory?

Junilu Lacar

Joined: Feb 26, 2001
Posts: 6529

You have to always be aware of the intended audience of the book. Is the sample code supposed to show a best practice or just illustrate how something works? A lot of code examples in "beginner" type books are meant to simply illustrate how something works; you would not actually code it that way in actual practice unless you really want to get fired. A VO (the preferred term now is Transfer Object) is meant to facilitate movement of data across layers so to go directly to a TO in the View is undesirable, IMO.
[ April 08, 2004: Message edited by: Junilu Lacar ]

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Marc Peabody
pie sneak

Joined: Feb 05, 2003
Posts: 4727

SCWCD Exam Study Kit [Deshmukh/Malavia] has a nice illustration on page 371.
Anyway, the View (JSP) can access the Model and/or the VO for population of values.
In true MVC the Model can also update the View but this isn't possible in web applications because the server can't "push" a new page to the user's browser.

A good workman is known by his tools.
I agree. Here's the link:
subject: mvc, VO, and tier leakage antipattern
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