How can I refresh a calling page on return from a TF activity ?

Question

Hi,
I have a (sounds easy) case where a view activity invokes a BTW with fragments. The called BTF has been declared with isolated data control scope. Inside the BTF some updates happen and when the BTF returns the calling view should display the modified data. The BTF should not be opened as a dialog and the above take place inside a region. There are examples in the Internet for how to implement such case but only calling a taskflow with pages from a dialog.
I tried creating first the Taskflow binding definition [19.10.1 How to Associate a Page Definition File with a Task Flow Activity|http://docs.oracle.com/cd/E35521_01/web.111230/e16182/taskflows_activities.htm#sthref539] , then I set the related operations (Execute, setCurrentRowWithKey, ...) in the Page Definition and invoke the operations inside the “After Listener” Listener (<after-listener>) of the taskflow activity but the binding context is not accessible inside the listener, I get NPE accessing the binding.
After some tests I have found that I can call the Operations using “#data.taskflowdefinition..” but I afraid using this technique because of so many papers stating that this is a bad practice.
Additionally I tested using an invokeAction in the calling page definition page and it works but I prefer “refreshing” the model from the activity (there are many pages calling the same activity).
I am wondering if there is a more elegant solution that I haven’t seen yet.
Thanks for any ideas,
Yiannis
Edited by: Tses on Mar 8, 2013 11:15 PM

Answer 1

Hi Timo and thank you for your reply,
As far as I know any method executed in the BTF has no effect in the calling page because of the isolated data control scope.
Consider the following layout of a very simple TF diagram. The BTF has "Share data controls with calling task flow" unchecked and "Always begin new transaction"
View --> Method Call --> BTF
Now imagine that a user navigates from the View to the BTF, make updates and finally commits the transaction from a taskflow return activity. The updates are executed inside the "private" BTF's data control scope because of the BTF settings.
Returning to the calling View the user sees stale data from the Data Control of the View, until he re-queries the model.
ADF supports execution of code during the call of the BTF (through Method Call) and also sending and returning parameters from the View to the BTF.
Conversely on return from the BTF there is no handler for executing code (something like "Return Method Call") in order to refresh (e.g. re-query and set current row) the View exploiting the return parameters.
The "After Listener" in the taskflow call activity has not access to the bindings context. Using #{data.bindingTFXXX} I guess that has a risk in a high availability environment for NPE where the http call to the BTF might be processed in a different server than the returning http call so the #{data.bindingTFXXX} might not exists.
The other solution I found using invokeAction with RefreshCondition depends on the returning values of the BTF, bloats the View with Bindings that I would prefer to be in a central place.
Am i missing something in the whole flow above ?
Yiannis