Web Application - MVC Layers

source found: http://www.javapassion.com/strutscodecamp/

Three Logical Layers in a Web Application: Model, View, Control
? Model (Business process layer)
– Models the data and behavior behind the business process
– Responsible for actually doing
? Performing DB queries
? Calculating the business process
? Processing orders
– Encapsulate of data and behavior which are independent of presentation
? View (Presentation layer)
– Display information according to client types
– Display result of business logic (Model)
– Not concerned with how the information was obtained, or from where (since that is the responsibility of Model)
? Controller (Control layer)
– Serves as the logical connection between the user's interaction and the business services on the back
– Responsible for making decisions among multiple presentations
? e.g. User's language, locale or access level dictates a different presentation.
– A request enters the application through the control layer, it will decide how the request should be handled and what information should be returned

Web Applications

• It is often advantageous to treat each layer as an independent portion of your application
• Do not confuse logical separation of responsibilities with actual separation of components
• Some or of the layers can be combined into single components to reduce application complexity

what's the different of these???

• logical separation of responsibilities
• actual separation of components