Lecture 3-System architecture 2

Question 1

What is the Model-View-Controller (MVC) used for?

Answer 1

Widely used for many object-oriented designs involving user interaction.

*part of the basic of the Smalltalk programming environment

Question 2

What are the 3 parts of MVC?

Answer 2

-Model –> application domain
-View –> display of the application’s state
-Controller –> user interaction with the model and the view

Question 3

What are the 3 responsibilities of the Model?

Answer 3

-Manages the behaviour and data of application domain
-Responds to requests for info about its state(usually from the view)
-Responds to instructions to change state(usually from the controller)

Question 4

What are the 2 responsibilities of the View?

Answer 4

-It renders the contents of a portion of the model’s data for visualization or interaction.
-If model data changes, the view MUST update its representation as needed using:
–push model :view registers itself with the model for change notifications (observer pattern)
–pull model: view calls model when it needs to update data

Question 5

What does the Controller do?

Answer 5

It translates the user’s interactions + view with it into actions that the model will perform.

Question 6

What are the 4 MVC interactions?

Answer 6

1.The model objects are created –> (each object is part of business model)
2.The views register as observes on the model objects–> model does not know that view or controller exist. it just sends notifications to all observers.
3.The controller is bound to a view–> (any action made by user through view will invoke a method in the controller class)
4.The controller is given a reference to the underlying model–> (when controller method is called, it triggers model’s functions/ state change)

Question 7

What is the MVC-I?

Answer 7

It’s a simple version of MVC architecture where the system is decomposed into two sub-systems :
-Controller-View
-Model

Question 8

What does the sub-system Controller-View do(2)?

Answer 8

-It takes care of input and output processing and their interfaces
-Registers with(attaches to) the data module

Question 9

What does the sub-system Model do?

Answer 9

It copes with all core functionality and the data

Question 10

What is the relationship between the 2 sub-systems?

Answer 10

The Controller-View is an observer of the data in the Model module

Question 11

Explain MVC vs Layered architecture(IA) for Dependency

Answer 11

MVC –> flow control is often bidirectional
LA–> flow control is unidirectional (each layer depends on layer under)

Question 12

Explain MVC vs Layered architecture(IA) for Responsibilities

Answer 12

MVC–> Model, View, Controller
LA–> Presentation, business logic , data access layer

Question 13

Explain MVC vs Layered architecture(IA) for Use cases

Answer 13

MVC–> often used in web, GUI desktop and some mobile apps
LA–>large scale enterprise apps