01. OAF Introduction

What is OAF ?

• Oracle Application Framework (OA Framework or OAF) is a proprietary framework developed by Oracle Corporation for application development within the Oracle E-Business Suite (EBS)
• Oracle Application Framework (OAF) provides visual and declarative approaches.
• The OA framework is also available to customers for personalization’s, customizations and custom-application development.
• The OA Framework helps in creating self Service pages in Oracle EBS.
• It controls the flow of the application.
• This framework works on the basis of Java EE principles.
• We must know the Basics of Core Java and Advanced Java to learn and incorporate OAF.
• In OAF User Interface is Very Interactive.
• We can view OA Framework pages in mobile phones which contain Internet browsing feature
• OA Framework is J2EE based but it also supports various standards like HTML, XML, SQL, and JSP.

Importance of OAF in Oracle Apps:

• These pages are designed in the user understandable format.
• It’s easy to deploy within a web browser.
• It gives better performance over Internet and has faster transaction rate.
• It requires no support or training for users and is more user friendly.
• Mainly it provides security, integration, and customization

Difference Between OAF and Oracle Forms

Let us discuss a few differences between OAF pages and Oracle Forms:
 

OAF	Oracle FORMS
OAF Follows MVC and Client Server Architecture	Forms Follows only Client Server Architecture
These pages are light weight components	These are not light weight components
OAF Pages can be sent through mobile devices	Cannot be sent through mobile devices
OAF Pages can be connected through Oracle Apps Local Machine	These cannot be connected (NOT APPLICABLE)
Good look and feel standards	Low look and feel standards when compared to OAF
OAF pages are integrated with the Java Top	Forms are integrated with Application Top
Commit command always occurs in the Application Module’s (AM) Java code. By this command, the data is transferred from OAF Cache to database.	The COMMIT_FORM or DO_KEY(‘COMMIT_FORM’) commands can be invoked by any trigger that allows restricted procedures.
A page is divided into regions. Regions contain fields, buttons, tables, and other components.	A form is divided into blocks; blocks contain the fields, buttons, and other components.

Structure of OAF

Let us discuss the architecture followed by OAF:

• As J2EE follows MVC architecture, OAF also follows MVC architecture as its based on and follows J2EE.
• The abbreviation of MVC is Model View Controller.
• MVC is the clean design interface between Model, View, and Controller.
• MVC is software pattern for implementing the user interface.
• It divides a software application into three interconnected parts which makes the implementation of request and response easier.

 Pic1:

Model mainly consists of application data, business rules, logic and functions.

Model contains the components which handles data directly from Database. It includes business components for Java which mainly are:

• Entity Object (EO)
• View Object (VO)
• Callable Statement (PL/SQL Statement)
• Prepare Statement (Single Select Statement)
• OADB Transactions (Oracle Apps Data Base Transactions)

View can be any output representation of information, such as a chart or a diagram. is nothing but the OAF Page Output.

View is implemented by UIX (User Interface XML). A view is told by the controller all the information it needs for generating an output.

The view is updated with the change and the representation as given by the model time to time.

The view in OAF comprises of various page level items like text fields, buttons, regions, links etc. These are visible on any OAF page.


Controller accepts input and converts it into commands for the model or view.It can also change the views presentation of the model.

Controller has got three methods:

• Process Request ( The request is called when the page is rendered)
• Process Forms Request (HTTP Get)
• Process Form Data (HTTP Post)

HTTP get: This method is used only to read the information. It is to obtain a resource without changing anything on the server.

HTTP Post: This method is used to modify the information and update the information on the server.
 The figure given below shows the interaction between Model, View, and Controller: 

   pic2:

We will discuss in detail about MVC architecture in the next chapters.

Onion Structure of OAF

• Onion structure is another structure of OAF.
• The OA Framework can be extracted into a series of concentric layers.
• Each layer knows only about its next consecutive layer.
• The below figure shows the Onion Structure, in which AM interacts with the VO.
• VO interacts with EO. EO interacts with Data Base.

Pic3:

• The core layer represents the database and the surface layer represents the application pages.
• In between is a number of business logic and user interface layers.
• This layering allows for generic code and components to be implemented at the inner layers to maximize their reuse across the outer layers

Advantages and Disadvantages of OAF

The advantages of OAF are as follows:

1. End user Productivity
2. Enterprise Grade Performance and Scalability
3. Highly extensible Architecture
4. These pages have only region and items, so we can develop pages faster.
5. Transaction rate is high when compared to internet.
6. Application Customizability.
7. Developer Productivity.
8. It mostly does not require support and training for users and is user friendly.

The disadvantages of OAF are:

1. Cannot see the layout at design time.
2. OAF Pages are integrated / compatible only with the Oracle Apps.
3. Drag and Drop options are not available.
4. More R&D is required to design a form layout which is time consuming.

  Courtesy: newtonapples.com