Check in filled values are correct

Question

Hello,
I have a web interface with two layouts, the first one is just a description and the second one where you enter data.
For the key figure concerned, they have to reach the number showed in the first layout distributing it in the second layout by diff characteristics.
I would like to make a check before the data is saved.
I would like to show a message like "the sum of the values you entered is greater(lower) than the numbers of employees in your team" ... etc...
Maybe a user exit function is to be created, but where to place it ? In the after data change function in the web application builder ? And how to generate the message in the user exit ?
Any help is welcome.
Regards.

Answer 1

I already did it ( the dubble click on the inputprocessing) since the beginning.
But in the method, i don't find the code you mentioned.
I don't see where the save button s treated. I fall down to others calls and methods, but deeper i fall on the standard UP... function modules.
This the code of method inputprocessing in our system :
method called from BSP when an event appears
method inputprocessing .
  data: page_name         type string,
        subordinate_event type string,
        ls_handler  type upwb_ys_handler,
        method_subrc type sysubrc,
        eventtype   type char2, " UPWB_Y_HANDLER_TYPE,
        id          type string.
get runtime event id from HTMLB
  if event_id = cl_htmlb_manager=>event_id. " HTMLB event?
    data: lr_htmlb_event type ref to cl_htmlb_event.
    lr_htmlb_event = cl_htmlb_manager=>get_event(
        runtime->server->request ).
    if lr_htmlb_event is not initial.
      event_id = lr_htmlb_event->id.
    endif.
  endif.
Set runtime environment for components
  cl_upwb=>bsp_oninputprocessing(
      event_id   = event_id
      runtime    = runtime
      navigation = navigation
      page       = page
      request    = request
      version    = version ).
  m_event_id = event_id.
  mr_navigation = navigation.
  mr_page = page.
  mr_request = request.
mr_response = response.
  mr_runtime = runtime.
  m_version = version.
The id before '-' is the component name, that fires the event
  split event_id at '-' into event_id subordinate_event.
By default no error in input check
  clear subrc.
Request handling
  data: l_request_no    type string.
  if mr_application is not initial. " (check: no session time-out)
    l_request_no = request->get_form_field( 'bps-request_number' ).
  if the request handling is active (backward compatibility)
    if request->get_last_error( ) = 0
       and l_request_no is not initial.
      if l_request_no <> cl_upwb=>get_parameter( 'bps-request_number' ).
      the request is NOT correct!!!
      => THE ERROR PAGE SHALL BE DISPLAYED
        cl_upwb=>set_parameter( param = 'bps-request_ignored'
                                value = 'X' ).
        subrc = 10. " skip PBO
        exit.       " skip PAI (input processing)
      else. " request OK...
      the request is expected, increase the request counter
        add 1 to l_request_no. condense l_request_no.
        cl_upwb=>set_parameter( param = 'bps-request_number'
                                value = l_request_no ).
        cl_upwb=>set_parameter( param = 'bps-request_ignored'
                                value = '-' ).
      endif. " request OK
    endif. " request handling is active
  endif. " no time-out
Timeout handling
  if mr_application is initial.    " session time-out
    concatenate runtime->application_name '_exit.htm?timeout=1'
        into page_name.
    if request->get_form_field( 'sapgui' ) is not initial.
      concatenate page_name '&sapgui=1' into page_name.
    endif.
    if request->get_form_field( 'sapframe' ) is not initial.
      concatenate page_name '&sapframe=1' into page_name.
    endif.
    navigation->goto_page( page_name ).
    exit.
  endif.
get page name
  page_name = mr_application->get_current_page( ).
process input
  loop at mt_handler into ls_handler where
      eventtype ca c_validation and
    ( page_name = page_name
      or page_name = '*' ).
    method_subrc = dispatch( ls_handler ).
    add method_subrc to subrc.
  endloop.
execute event handlers
  if subrc = 0.
    eventtype = ce_event. " normal events
  else.
    eventtype = ce_exit_event. " exit events
  endif.
  loop at mt_handler into ls_handler where
      eventtype = eventtype and
    ( event_id = event_id
      or event_id = '*' ) and
    ( page_name = page_name
      or page_name = '*' ).
  call handler when no error in PAI or exit event
    dispatch( exporting is_handler = ls_handler ).
    if eventtype = ce_exit_event and ls_handler-event_id <> '*'.
      clear subrc. " process PBO on exit event
    endif.
  endloop.
endmethod.