Doubt in Workflows using Programming Exits on OO ABAP

Question

I have a doubt on workflows:-
Let me brief you about my requirement:
I am trying to update some Master data using ABAP Methods through Programming Exits in a Workflow.
I managed to find an OO method that can fetch the workflow container values directly into the structure.
While testing the workflow:-
The OO ABAP method executes and successfully updates the master tables.
However, a calling method (that triggers this method indirectly), raises an exception called SWF_RUN_WIM_EXEC_INTERRUPTED.  
The exception is caught within the caller method and the workflow errors saying that “the method ABC… cannot be executed.”
The caller method is:-
CL_SWF_RUN_WORKFLOW_START
The exception is raised on execution of the following statement:-
CALL METHOD me->start_workitem( lh_wi_handle ).
One reason for this is that the workflow is still not completed and still in “READY” state.
Alternative method
Once the Master data is updated successfully,
I tried to use the FM SAP_WAPI_WORKITEM_COMPLETE to end the work item or tried another FM to suspend the workflow.
Now it gives an error saying that these FMs are restricted from use during run-time execution.
Query
Do you have an idea why the exception is raised and how to track/prevent the same?
Can you suggest any other alternative?  Your valuable advice is urgently needed.
Thanks a million in advance,
Best Regards,
Vinod

Answer 1

Check the code
      CLASS zcl_event_handler IMPLEMENTATION
CLASS zcl_event_handler IMPLEMENTATION.
Top-of-page event
  METHOD top_of_page.
    PERFORM event_top_of_page
            USING z_dyndoc_id.
  ENDMETHOD.   "METHOD top_of_page
Change Status Button
  METHOD handle_toolbar.
    IF NOT pa_prodr IS INITIAL.
      DATA: lz_toolbar  TYPE stb_button.
      CLEAR lz_toolbar.
      MOVE    'CHANGE_STATUS'  TO lz_toolbar-function.
      MOVE    text-001         TO lz_toolbar-text.
      APPEND  lz_toolbar       TO e_object->mt_toolbar.
    ENDIF.          "IF NOT pa_prodr IS INITIAL
  ENDMETHOD.   "METHOD handle_toolbar
Handle User Command
  METHOD handle_user_command.
    CASE e_ucomm.
      WHEN 'CHANGE_STATUS'.
        LOOP AT    it_output
             INTO  wa_output.
          IF wa_output-chk_box EQ kc_x.
            z_flag = 1.
            EXIT.
          ENDIF.          "IF wa_output-chk_box EQ kc_x
        ENDLOOP.      "LOOP AT it_output INTO  wa_output
        IF z_flag EQ 1.
          PERFORM display_selected_data.
        ELSE.
          MESSAGE i001(zzrefn01)
                  WITH text-023.
        ENDIF.       "IF z_flag EQ 1
    ENDCASE.      "CASE e_ucomm
  ENDMETHOD.   "METHOD handle_user_command
ENDCLASS.   "zcl_event_handler IMPLEMENTATION