The Controller responds to user action and direct application flow. It provides the wiring between the UIX web bean and the middle-tier. All the controllers that we create subclass the
oracle.apps.fnd.framework.webui.OAControllerImpl.
When the browser issues an OA.jsp request:-
The oracle.apps.fnd.framework.webui.OAPageBean(the main OA Framework page processing class) uses the page name to determine which root AM it refers to, so that the VO’s related to the page can be accessed. Then user session is validated and then OAPageBean evaluates request parameter or figure out if it dealing with an HTTP POST or GET request. During the iteration, if the framework finds a web bean referencing a controller class it will call one of the following methods.
Process Request - This phase is invoked upon a browser 'Get' or redirect/forward. This is where
custom code can call the application module to initialize and query the data. This phase may
optionally construct or modify the web beans to create or alter the page structure and web bean
properties.
Process Form Data - This phase is invoked upon a browser 'Post'. During this phase the
framework will automatically applies form changes back to the underlying view objects. Rarely is
custom code required in this phase. If exceptions are thrown during this phase, the Process Form Request phase is skipped and the page is redisplayed.
Process Form Request - This phase is invoked upon a browser 'Post', assuming no exceptions
were thrown during the Process Form Data phase. This is were custom code can handle the form
submit events and call the application module to process the event.
Framework passes two parameters OAPageContext and OAWebBean to the processRequest and processFormRequest.
Following are the usages of OAPageContext parameters.
1. To get and set values of the fields, using oapagecontext.getParameter and
oapagecontext.putParameter
2. For redirecting to the current page or another page. For example to redirecting to current page
itself use oapagecontext.forwardImmediatelyToCurrentPage. Or you may use
oapagecontext.sendRedirect(snewpage)
3. To get a handle to application module(remember we attached AM to page)
oapagecontext.getRootApplicationModule()
4. Write debug messages, using oapagecontext.writeDiagnostics
5. Get message text from FND Message dictionary, using oapagecontext.getMessage
Usages of parameter OAWebBean:-
Remember that webbean represents the hierarchy/structure of components in the page. Hence
using this paremeter object, you can get a handle to any bean/component in that page hierarchy.
Once you have a handle to that bean (say field bean or button bean), you can then invoke methods like setRendered etc to change the behaviour of page at runtime.
Some examples are
1. OAWebBean LastName = oawebbean.findIndexedChildRecursive("personLastName");
Note: In this example, our page must have just one field whose name is personLastName
2. Get a handle to region
OAStackLayoutBean oastacklayoutbean =
(OAStackLayoutBean)oawebbean.findIndexedChildRecursive("stackRegionName");
Source: http://kohlivikram.blogspot.in/search/label/OAF
