CO (Controller)

CO stands for Controller.

Controller will take care about the web browser activities.
The controller will manage between the flow of the pages.
Controller will respond to the user actions and directs application flow.
The controller will request from HTTP Get and HTTP Post.
All the controllers end with CO
When create controller one subclass will generate.

Controller is the java file and can be associated to a complete OAF page or to a specific region.

Controller responds to the user actions .

the controller will request from http get and http post .

when you create the controller one sub class is going to generate (path:oracle.apps.fnd.framework.webui.OAcontrollerImpl).

There are several tasks you will do routinely in your code.

1)Handle button press and other events

2)Automatic queries

3)Dynamic WHERE clauses

4)Commits

5)JSP Forwards

The logic for accomplishing all these tasks is written in controller

**Http get-when page opens the default data loads Vs Http Post :After page opens ** 

Controller Methods:

Process request(http get) 

process form request (http post)

process form data(http post )

1) Process request(http get):

a) while loading the page to display default items we will use process request 

b) this phase is invoked upon browser http get.

2) process form request (http post): 

a)After Loading the page performs any actions will use process form request 

b)this phase is invoked upon browser http post .

3) Process form data: 

if exceptions are thrown during this phase process requests or process form request phases are skipped & the page is re displayed ( error page).