Basics of OA Framework - Model View Controller (MVC) Architecture

Part3:-
Model View Controller (MVC) Architecture:-

MVC Architecture stands for Model View Controller.



Model:-
==============
The Model Layer encapsulates the under lying data and business logic of the application. The Model layer represents the BC4J components which consists of the

· Application Module
· Entity Object
· View Object.
· Association Object
· View Link

Application Module:-
The Application Module defines the logical data and business methods. The Application Module handles the transaction and interacts with clients. It serves as containers for related BC4J objects. AM is responsible for establishing database connections and transaction context. AM's can be nested to provide more complex application modules. Every OA Page should have at least one Application Module associated with it.

Entity Object:-

Entity object encapsulates the business rules and logic. Entity object is used when there is a Insert, Update or deletion of data. All data validations across the application is provided by the EO. EO's can be linked with each other to create an Association object.

View Object:-

View Object encapsulate a database query. It iterates over the result set. View Object may be based on a simple select query or be based on an single or multiple EO's. VO acts as a single point of contact for getting and setting entity object values. View objects can be linked to form View Links. All VO's should be associated with an AM before usage.

Association Object :-

Association Object is used to join two or more Entity Objects together.

View Link:-

A view link is an active link between view links. A view link can be created by providing the source and destination views and source and destination attributes.
There are two modes of View link operation that can be performed. A document and Master/Detail operation.

View:-

The View Layer of the MVC architecture consists of page which in turn contains Regions and Items. Never confuse View with View Object. View Object is part of BC4J Layer( Model ).

Controller:-

Controller handles the user actions. OA Framework Controller has three methods. Below are the list of methods:
1. processRequest         - Fires when page is rendered.
2. processFormData      - Fires when page submit happens.
3. processFormRequest - Fires when Fire Action/Fire Partial Action and Page submit happens