javamvcpython
In MVC applied to WSGI or Java EE, is the Servlet a controller, dispatcher, or both? I think I've seen system diagrams where the controller and the dispatcher are different. Could the controller control SQL statements which should not be in the dispatcher?
Thank you
First I think is best talk about what is MVC Architecture and then go further into the way you are currently programming.
The MVC Architecture is way to organize the workflow inside a sotfware sistem, think about it as a layered way to implement system behaviour. This layers are:
Model: Represents your Data Model, its the system core where all information related to it should be localized. So for example: if you are going to desing a Game you'll need Players, Rules, Obstacles, and some logic related to the interactions of this elements such as : Players should be able to sort Obstacles when some set of Rules apply.
The Model is the first think you should think off because its going to be the center of your applications.
Controller: This is where the magic happens and where the Layered Architecture meets the Object Oriented Paradigm it was intended to use. Here is where you implement how does the system reacts when some application user request something about the app vai the user interface.
The Controller should be able to handle the Model Objects, do operations with them to achieve what the user requested and then delegate the result to the corresponding View Layer to render it back to our user.
View: This is the Start and End Point of User interactions. Here is where you define how users interact with the application. Nowadays is quite common users try to access, for example, web applications from different kinds of media such as: Mobile Phones, Tables, Pcs, Laptops, etc.
Generally each techonologie needs a diferent language to create the view, so imagine that your Data Model and the way that model interacts and how you render that interactions is all hardcoded, there is absolutely no way to reuse your code in a way that is not CopyPaste. The result is code that smells and lots of time wasted adapting the HOLE sysmte.
The virtude of having the View in a separated layer, allow us to work independently from the Model we are currently working on. We only need to know how we should render the list of objects the controller is sendng us. How did he generated it is completly trivial
So , finally we got an independet Model that could be adapted as we see fit according to our current needs (today i need to handle a Monouser Game with no rules, tomorrow i whan to play with friends and now its Multiuser, and so on) that not depends on how are we going to render it to the user. Then, a Controller that captures users request that came from a view , process Model Objects, and then gives the information back to the View to render it.
Back to the first question you asked: Like you can see (i hope) MVC is a WAY to do things and not a TECHNOLOGIE to create software. You could use your java Servlets, and implement a MVC Achitecture under it.
Here is a Q&A example site using a MVC Architecture to clarify a little
JavaScript MVC is just a code organization pattern.
They happen to work well with SPA but they can be used in normal applications.
However you don't actually need a JS MVC framework. You can just write modular JavaScript using some kind module loading strategy.
As long as you separate modules into separate objects / functions / units the code should be structured and clean.
Best Answer
Controller
The controller is the initial contact point for handling all requests in the system. The controller may delegate to a helper to complete authentication and authorization of a user or to initiate contact retrieval.
Dispatcher
A dispatcher is responsible for view management and navigation, managing the choice of the next view to present to the user, and providing the mechanism for vectoring control to this resource.
A dispatcher can be encapsulated within a controller or can be a separate component working in coordination. The dispatcher provides either a static dispatching to the view or a more sophisticated dynamic dispatching mechanism.