OVS F4 help in Standard application in Webdynpro ABAP

METHOD ovs_firstname .
* declare data structures for the fields to be displayed and
* for the table columns of the selection list, if necessary
  TYPES:
    BEGIN OF lty_stru_input,
*   add fields for the display of your search input here
      firstname TYPE bu_namep_f,
      secondname TYPE bu_namep_l,
    END OF lty_stru_input.
  TYPES:
    BEGIN OF lty_stru_list,
*   add fields for the selection list here
      firstname TYPE bu_namep_f,
      secondname TYPE bu_namep_l,
    END OF lty_stru_list.

  DATA: ls_search_input  TYPE lty_stru_input,
        lt_select_list   TYPE STANDARD TABLE OF lty_stru_list,
        ls_select_list   LIKE LINE OF lt_select_list,
        ls_text          TYPE wdr_name_value,
        lt_label_texts   TYPE wdr_name_value_list,
        lt_column_texts  TYPE wdr_name_value_list,
        lv_window_title  TYPE string,
        lv_table_header  TYPE string.

  FIELD-SYMBOLS: <ls_query_params> TYPE lty_stru_input,
                 <ls_selection>    TYPE lty_stru_list.

  CASE ovs_callback_object->phase_indicator.

    WHEN if_wd_ovs=>co_phase_0.  "configuration phase, may be omitted
*   in this phase you have the possibility to define the texts,
*   if you do not want to use the defaults (DDIC-texts)

      ls_text-name = `FIRSTNAME`. "must match a field in list structure
      ls_text-value = `First Name`.
      INSERT ls_text INTO TABLE lt_column_texts.

      ls_text-name = `SECONDNAME`.
      ls_text-value = `Second Name`.
      INSERT ls_text INTO TABLE lt_column_texts.

      APPEND LINES OF lt_column_texts TO lt_label_texts.

      ovs_callback_object->set_configuration(
                label_texts  = lt_label_texts
                column_texts = lt_column_texts
                window_title = lv_window_title
                table_header = lv_table_header ).

    WHEN if_wd_ovs=>co_phase_1.  "set search structure and defaults
*   In this phase you can set the structure and default values
*   of the search structure. If this phase is omitted, the search
*   fields will not be displayed, but the selection table is
*   displayed directly.
*   Read values of the original context (not necessary, but you
*   may set these as the defaults). A reference to the context
*   element is available in the callback object.

      ovs_callback_object->context_element->get_static_attributes(
          IMPORTING static_attributes = ls_search_input ).
*     pass the values to the OVS component
      ovs_callback_object->set_input_structure(
          input = ls_search_input ).

    WHEN if_wd_ovs=>co_phase_2.
*   If phase 1 is implemented, use the field input for the
*   selection of the table.
*   If phase 1 is omitted, use values from your own context.

      IF ovs_callback_object->query_parameters IS NOT BOUND.
******** TODO exception handling
      ENDIF.
      ASSIGN ovs_callback_object->query_parameters->*
                              TO <ls_query_params>.
      IF NOT <ls_query_params> IS ASSIGNED.
******** TODO exception handling
      ENDIF.

*     call business logic for a table of possible values
*     lt_select_list = ???

      "=============================================
      "Prepare sample list for value list
      "=============================================
      CLEAR lt_select_list.

      CLEAR ls_select_list.
      ls_select_list-firstname = 'Ramakrishnappa'.
      ls_select_list-secondname = 'Gangappa'.

      APPEND ls_select_list TO lt_select_list.

      CLEAR ls_select_list.
      ls_select_list-firstname = 'Abc_First'.
      ls_select_list-secondname = 'Abc_Second'.

      APPEND ls_select_list TO lt_select_list.
      "=============================================
      ovs_callback_object->set_output_table( output = lt_select_list ).

    WHEN if_wd_ovs=>co_phase_3.
*   apply result

      IF ovs_callback_object->selection IS NOT BOUND.
******** TODO exception handling
      ENDIF.

      ASSIGN ovs_callback_object->selection->* TO <ls_selection>.
      IF <ls_selection> IS ASSIGNED.

        ovs_callback_object->context_element->set_static_attributes(
                               static_attributes = <ls_selection> ).

      ENDIF.
  ENDCASE.

ENDMETHOD.

METHOD _pst_dqxnmttuzezeszudlnztqzh4u .
  "Exit of WDDOMODIFYVIEW (in YDEMO_OVS_HELP )
  DATA lo_node TYPE REF TO if_wd_context_node.

  DATA lo_node_info  TYPE REF TO if_wd_context_node_info.

  CHECK first_time EQ abap_true.

  " Get node ref
  "==========================
  lo_node = wd_context->get_child_node( name =
wd_this->wdctx_personaldata ).

  " get node info reference
  "=============================
  IF lo_node IS BOUND.
    lo_node_info = lo_node->get_node_info( ).
  ENDIF.
  " Rerurn the control if lo_nod_info is not bound
  "==========================
  IF lo_node_info IS NOT BOUND.
    RETURN.
  ENDIF.
  " set the value help for attribute: firstname
  "==========================
  lo_node_info->set_attribute_value_help(
    EXPORTING
      name            = 'FIRSTNAME'
   value_help_mode = if_wd_context_node_info=>c_value_help_mode-ovs
      value_help      = 'OVS_HELP'
  ).
ENDMETHOD.