Retrieve workflow container data in programming exit

Question

I am trying to use a programming exit in Workflow in order to amend the task container for the receipients field of a "Send Email" step. The reason why we are not determining the receipients in the usual way is because we hold the receipients (amongst other data) in a separate Z* table - this needs to stay this way.
I created a class and copied method CHANGE_CONT_ELEMENT to base my altered code on. The method is triggered fine when testing the workflow. Here is what it now looks like:
method CHANGE_CONT_ELEMENT .
  DATA: container TYPE REF TO if_swf_cnt_container,
        if_swf_cnt_container,
        cont TYPE REF TO IF_SWF_IFS_PARAMETER_CONTAINER,
        name TYPE swfdname,
        lh_wihandle TYPE REF TO if_swf_run_wim_internal,
        l_exception TYPE REF TO cx_swf_cnt_container,
        l_wiid TYPE sww_wiid,
        w_container type ref to IF_SWF_IFS_PARAMETER_CONTAINER,
        w_names type SWFDNAMTAB,
        wa_names type line of SWFDNAMTAB,
        w_value(30).
  w_container = me->m_ctx->GET_WI_CONTAINER( ).
  w_names = w_container->LIST_NAMES( ).
data: w_name type SWFDNAME.
w_name = 'TEST-NUMBER'.
TRY.
  loop at w_names into wa_names.
    CALL METHOD w_container->get
     EXPORTING
      name       = wa_names.
  endloop.
CATCH CX_SWF_CNT_ELEM_NOT_FOUND .
CATCH CX_SWF_CNT_ELEM_TYPE_CONFLICT .
CATCH CX_SWF_CNT_UNIT_TYPE_CONFLICT .
CATCH CX_SWF_CNT_CONTAINER .
ENDTRY.
ENDMETHOD.
Now w_names retrieves the names of the fields fine (including my "TEST" entry which I declared in the Workflow Builder), but the GET method causes a "CX_SWF_CNT_ELEM_NOT_FOUND" exception.
Is this the correct way to retrieve data out of a Workflow container within a WF programming exit? What am I doing wrong?
Kind regards,
Michael Koch

Answer 1

Hi Michael, Paolo & Other experts,
I am trying to understand when, why and how to use a 'programming exit' in a SAP workflow.
(1) Did you figure out the solution to your problem?
(2) Is there any material / tutorial on use of a  'programming exit' in a workflow?
Thanks
Abaper