ADF / Webcenter : POJO Data Control caches values even when container taskflow is refreshed [UI Aware Data Model - I]

Oracle says ADF BC , EJBs , Webservices , POJOs etc. are supported as Business Services layer in ADF.

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#CHDEIFBB

Example 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.

ADF : Lifecycle of a POJO Data Control

Though ADF BC is the Oracle recommended Business Services layer , but for many use cases  we end up using POJOs and exposing them in the UI via POJO Datacontrols

e.g. consuming Webservices as WS Proxy , calling 3rd party or IDM APIs

I would like to point out that its highly recommended that you generate datacontrols out of the POJO and consume them in the UI rather than get a handle to the POJO directly in the UI surpassing any binding layer per se. That ways we can leverage cool features like sorting , filtering etc OOTB as well as the results are not cached when the table is bound to a pageFlowScope bean.

I have seen even ignorant so called 'Sr Solution Architects' use the wrong approach & face weird issues & blame it on ADF !!

This post is intended to share the insights I received from Oracle PMs and others on the popular ADF Enterprise Methodology Group (EMG) on the below use case.

A POJO  in the model layer with its constructor and a few public methods which return a list or the like which is finally exposed as a Datacontrol to a ADF UI.

When will the POJO Datacontrol and the POJO be initialized and in what memory scope would it be kept in case it needs to be accessed in various places on the same page or in different pages in same/different TFs ?

See   the ADF EMG post & Frank's reply on the forum post for more details  and precise answers on the above.

Getting Started with BPM 11g

Following links should help you get jump started pretty quick since quite a few of them are video tutorials-

1)http://www.oracle.com/technetwork/middleware/bpm/learnmore/bpmwebinarseries-361340.html (Collated BPM Webinar)

2)http://andrejusb.blogspot.in/2010/10/initializing-oracle-bpm-11g-process.html (Initializing Oracle BPM 11g Process Payload from Oracle ADF 11g)

How ADF BC and BPM Payload  Interact

3)Building a sample BPM Process http://www.oracle.com/webfolder/technetwork/tutorials/obe/fmw/obpm/11g/r1/firstProcess/firstprocess_obpm11g.htm