MVC (I'm gonna get it right this time)

Question

When I started my project, I didn't even know what Model-View-Controller was. Now it's all to clear that my app is totally convoluted because I didn't use it. So I want to get it ABSOLUTELY right this time. I'm hoping to get a better idea of the responsibilities of each part
the closest thing to my project would be a midi sequencer.
What I know,
the model objects should contain all the data of where notes appear, velocities, tracks etc.
The view contains the code to draw to the screen and interpret user input.
What I want to know
� How to split responsibilities between the view and the controller?
� Should a list of the currently selected notes be stored in the view or controller?
� When the user clicks and drags some selected notes, What should the message from view to controller be?
ie "clicked and draged" or "change pitch of selected notes" or "change pitch of these specific notes????
� Should the view remember all the notes on a track or just the ones currently in view?
� Which part should do the reading/sending of notes the controller or the model?
Obviously the view objects shouldn't be as "stupid" as my computer monitor, but I'm still a bit confused... can anyone shed some light on the subject or provide some good reading? all the examples I see use simple 3 button apps which aren't very educational in terms of concepts
thanks all,
-matt
ps(I wont be using the included midi sequencer objects)
Edited by: Mat on Nov 7, 2007 2:55 PM

Answer 1

Your question requires a whole session on MVC pattern but to summarize the explanation to understand it practically, here are the components and where they fit in MVC.
Database - Model
JSP - View
Java/EJB/etc - Controller
Lets take an example for the above 3:
You have a user registration page, once the user enters his details, they will be validated and stored into a database table.
So the user registration page will be our JSP page and will be the view, this JSP page will invoke the controller which is nothing but a java class that handles or validates the data inserted by the user on the JSP page. This controller will then insert this data into the database table. Once it is successfully inserted, the controller java class will send a message to another JSP which will again display that message to the end user.
So this is how MVC works.
I hope this helps you a bit.
Choicest Regards
Amit Singh Rathore
www.proamit.com