Background of Oracle Application Framework

Basic Information and little bit background of OAF-

Oracle Application Framework (OA Framework) is the Oracle Applications development and deployment platform for HTML-based business applications.

Fig. Simple Web Application Architecture

Application Tier Contains a Web Server, which maintains the components such as Servlet, JSP:

Component is nothing but piece of code, which implements well defined interface.
A Single Component is not an Application. An Application consists more than one number of components working together.
Component handles complete task, such as Business Logic, Database Transactions Logic and Presentation Logic.

Few are the disadvantages were observed in this architecture :

1. Only One Application developer has to develop the complete component
2. Application developer has to concentrate on Business Logic, Database Transactions Logic as well  as Presentation Logic.
3. Application Developer Must have the Multiple Skills
4. Development Time is more
5. Lot of confusion with Business Logic, Database Transactions Logic and Presentation Logic since they are being developed as single component.

To overcome the above disadvantages MVC1 Architecture was introduced :

Fig. MVC1 Architecture

• Model (M): Model Represents data object. Model is what is being manipulated and presented to the user.
• View (V):    Serves as Screen representation of Model. It is the object that presents the current state of the data objects to user.
• Controller (C):  Defines the way user interface reacts to the user’s input. The Controller component is the object that manipulates the model or data object.

In MVC1 Architecture

• Servlet/JSP acts as View as well as Controller.
• Java Bean acts as Model Component.

Below are the disadvantages of MVC1 architecture:

1. Only One Application developer has to develop the component with Business Logic, as well as Presentation Logic.
2. Application developer has to concentrate on Business Logic as well as Presentation Logic.
3. Application Developer Must have the Multiple Skills.
4. Resources such as Java developers and Web developers can not be used effectively.
5. Development Time is more.

To overcome the above disadvantages MVC2 Architecture has been introduced:

Fig. MVC2 Architecture

MVC is divided as below :

• Model :  Java Bean acts as Model. It is Java Bean called as Form Bean. It will receive the client data through the Controller and performs the data validations or data base transactions such DML operations. After performing database transactions it provides the data for the view.
• View : JSP acts as View. It populates the data from the Form Bean ( Model ) and Present to the user.
• Controller : Here Servlet acts as Controller. It is java Servlet called as Action Servlet. It receives request from the web client and stores data into the Java Bean called as Form Bean (Model) and receives response (success / fail) from the Form Bean. Based on the response from Form Bean, Action Servlet decides, which page (view) to be presented to the client.