It is almost and instantaneous whenever I talk to developers about Model View Controller (MVC) they say you make a request to a url the server builds a entity (MODEL) and provides you with visual representation of that model.
So does this mean MVC is only for the web or have I been meeting people who are just developers who employ MVC for writing web applications?
Are there usages for MVC on desktop style applications?
I for one am new to paradigm and would like to know of any super-set to MVC
MVC is a pattern. Patterns apply across all programming. MVC just happens to work very well in a web context.
As gnat points out just have a look at the mvc tag and you will see multiple examples of it being implemented.
Considering that MVC is from 1977, and the web was only invented in 1991, it should be pretty obvious that MVC is not only for the web.
No, development for OS X and iOS uses Model View Controller pattern.
Ask the question in a Microsoft environment and many people will assume you mean Asp.Net MVC which is an MVC implementation specifically for the web.
Unfortunately there are many people who do not realise that this is an implementation of the MVC pattern and think they are interchangeable terms, which leads to an assumption of "web only".
At least as far as I know, the first implementation of MVC was in Smalltalk. It was definitely present in Smalltalk-80. Though I don't have any documentation handy to prove it, I believe it (or something quite similar anyway) had been in Smalltalk for a few years by then.
Most OO GUI frameworks have included at least some variant of MVC. I'm not sure, however, exactly what "superset" would mean in this case. It's a little hard to say whether any given variant is a superset, subset, or peer of MVC, but I'd tend to consider most of them peers.
In any case, many (most?) of these have been used for desktop development, not web development. Thanks to some old AT&T patents, most windowing systems require programs to be able to re-generate views on demand. This (almost) forces at least some degree of separation between code that maintains the current state (the model) and code that displays that state (the view). That still leaves a lot of room for variation in 1) the degree to which the controller functionality is isolated, and 2) the exact details of where to draw the lines between each of the major pieces.
No, it applies even for standalone applications. Example Java Swing follows MVC.
So there is a lot of different design patterns in this area.
and so on. Over the years these have been intertwined, mashed together, changed and applied in a wide variety of contexts. The important bit here, is that the MVC design pattern from 1977 has changed quite a lot, and is no longer the design pattern used by serverside web frameworks. As an example in the original smalltalk implementation the Model would observe the view for changes, which is no longer the case as the serverside simply can't observe html elements in the users browser. Instead if the view changes, the view will send a request to the controller which will then update the view. Again the original MVC implementation is not followed, as an update to the model would imply that all views dependent on the model would be updated.
The modern web frameworks follows a simple three tier architecture also known as a Model 2 architecture.
There are of course examples of real MVC architectures on the web, but these are often client side only, connected to a server which follows the Model 2 architecture, as the views are xml and json, and not observed for changes. Examples of client side pure mvc architectures are Sencha Touch and Sproutcore.
If you have MVC in the browser, mvc like on the server, and mvc like as the data layer, you have a hierarchial mvc implementation.
Note. I've only talked about web frameworks, other implementations of MVC such as java swing and Flex has other implementation differences.
One thing you must know is that there are as many flavours of MVC as there are frameworks that claim to implement MVC.
Most agree on the fact that the Model holds some state and the View renders it. But the Controller has very different roles.
In Smalltalk, where it was first described, the Model is the core of your application, data and business methods. The View is a graphical representation of the state of the application (aka Model), and the Controller manages the user input, mouse and keyboard events. The Controller, for instance, routes keyboard events to the view element that has the focus.
In .jsp pages, the Model is mostly data, the View renders that Model to HTML and the Controller does the routing of the Model to the proper View to render it.
So, to answer your question, while MVC is used both on standalone applications (Java, .Net, Flex) and the web (jsp pages), it is a very different thing. That means the MVC you know is not used in standalone applications.
