Call transaction in new session (but only one)

Question

Dear all,
as a hotspot functionality I would like to open a new transaction in a new session. For that reason, I use the FM ABAP4_CALL_TRANSACTION with the option STARTING NEW TASK.
However I would like to restrict the new tasks in a way that only one session is used (no matter how often the user clicks the hotspot. Kind of like the ABAP Help in the workbench.
I checked the class CL_IMC_MODE to see if it could work as a new internal session but the new mode dumped when I pressed the back button and according to the dump Statements that closes the internal mode unexpectedly like LEAVE are not allowed. Since I call standard transactions (like VA03) I can hardly prevent that. Did I miss something or do you have any other idea how I could solve my problem?
Thank you for any input.
Christian

Answer 1

Hi Christian,
Here is a sample code that takes in a sales order number, displays the document number as hotspot and when the user clicks on the hotspot, it opens a new window for displaying the order. No matter how many times the user clicks on the hotspot, it will only display one window for VA03. I hope this solves your problem.
REPORT ztest.
PARAMETERS: p_vbeln LIKE vbak-vbeln.
DATA: ls_vbak LIKE vbak.
DATA: BEGIN OF i_rfc_spagpa OCCURS 0.
        INCLUDE STRUCTURE rfc_spagpa.
DATA: END OF i_rfc_spagpa.
DATA: v_mode LIKE sy-index.
START-OF-SELECTION.
  SELECT SINGLE * FROM vbak
                  INTO ls_vbak
                 WHERE vbeln = p_vbeln.
  IF sy-subrc <> 0.
*-- error.
  ENDIF.
  WRITE:/ ls_vbak-vbeln HOTSPOT,
          ls_vbak-vkorg.
AT LINE-SELECTION.
  CASE sy-ucomm.
    WHEN 'PICK'.
*-- Delete the previous session and then call VA03 in a new session
      CALL FUNCTION 'TH_DELETE_MODE'
           EXPORTING
                mode = v_mode.
      CLEAR: i_rfc_spagpa, i_rfc_spagpa[].
      i_rfc_spagpa-parid = 'AUN'.
      i_rfc_spagpa-parval = p_vbeln.
      APPEND i_rfc_spagpa.
      CLEAR i_rfc_spagpa.
      CALL FUNCTION 'ABAP4_CALL_TRANSACTION' STARTING NEW TASK 'TEST'
        EXPORTING
          tcode                         = 'VA03'
          skip_screen                   = 'X'
          mode_val                      = 'A'
          update_val                    = 'A'
*       IMPORTING
*         SUBRC                         =
       TABLES
*         USING_TAB                     =
          spagpa_tab                    = i_rfc_spagpa
*         MESS_TAB                      =
        EXCEPTIONS
          call_transaction_denied       = 1
          tcode_invalid                 = 2
          OTHERS                        = 3 .
      IF sy-subrc <> 0.
        MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
                WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
      ENDIF.
    WHEN OTHERS.
  ENDCASE.