The Data control layer which happens to be the Model layer can be generated from each of the above ( gets generated automatically from ADF BC).
Use Case -
I had a taskflow which contained a jsff as a default view activity. The view in turn pulled data from a Webservice proxy (a POJO for all practical purposes) via a POJO DataControl.We had a requirement to refresh the taskflow when the value of a selectOneChocie outside the region changed .
Issue -
Though the taskflow refreshed but the page showed the same data within the ADF Table (based on the POJO Data control) which was surprising !
Concern -
Since as per the documentation -
http://docs.oracle.com/cd/E21764_01/web.1111/b31974/taskflows_regions.htm#CHDEIFBBExample 17-8 says :
You do not need to refresh an ADF region to refresh the data controls inside the ADF region. During the ADF lifecycle, the refresh events telling the iterators to update will be propagated to the binding container of the current page of the ADF region.
Solution -
We had to re-execute the iterator's Query to get this to work either as a method call before your view is loaded or by overriding the refreshRegion() method of the Region Controller class.
Explanation -
The actual reason why this is expected is because the way ADF works with ADF BC as the business services layer and the UI-aware data model aspect from the Oracle documentation. Other non - ADF BC business services implementation donot support this pattern and we would need to refresh iterators programmatically or clear cache's etc to reflect most recent data when using POJO's/ WS Datacontrols etc.
"When you use ADF Business Components in combination with the ADF Model layer and ADF Faces UI components, the data model is "UI aware" because your UI components will automatically update to reflect any changes to the row sets of these business objects
Thus, the UI-aware data model represents a solution that works across application technology layers to ensure that the UI and data model remain synchronized."
Here is the forum thread for reference.
Conclusion -
Though many people who have worked in open source platforms and are used to having a handle to the code aren't fans of ADF BC - but ADF BC simplifies development by providing really cool features like the UI Aware Data Model.I would try to outline more in this in another post.