#3 The Cost of a Screen

An ABAP team needs a screen. Not an application — a screen. A maintenance view for a customising table nobody wants to explain in SM30. A cockpit showing what last night's job actually did. An approval step for one department.

The logic behind such a screen is often thirty lines. The cost of putting a user interface in front of those thirty lines is not, and it does not scale down with them: a data model to declare, a service to define, a binding, an annotation model, a frontend artefact, a deployment — and an object that now exists forever, has to be transported, has to survive an upgrade, and one day has to be deprecated by someone who never met the department that asked for it.

None of that is waste. It is what makes a real application dependable. It is simply a fixed cost, and a fixed cost is brutal to a small thing.

So the screen does not get built. Or it becomes a selection screen and an ALV grid, and everyone agrees to stop thinking about it. Every system has a Z package full of those.

Here is the job monitor instead. Not an excerpt — the whole application:

CLASS zcl_job_monitor DEFINITION PUBLIC.

  PUBLIC SECTION.
    INTERFACES z2ui5_if_app.

    TYPES:
      BEGIN OF ty_s_run,
        job    TYPE string,
        finish TYPE string,
        state  TYPE string,
      END OF ty_s_run.

    DATA runs TYPE STANDARD TABLE OF ty_s_run WITH EMPTY KEY.

  PROTECTED SECTION.
    DATA client TYPE REF TO z2ui5_if_client.
    METHODS set_view.
    METHODS model_init.

  PRIVATE SECTION.
ENDCLASS.


CLASS zcl_job_monitor IMPLEMENTATION.

  METHOD z2ui5_if_app~main.

    me->client = client.
    IF client->check_on_init( ).
      model_init( ).
    ENDIF.
    set_view( ).

  ENDMETHOD.

  METHOD set_view.

    DATA(view) = z2ui5_cl_ui5_view_builder=>factory(
        )->ele( n = `View` ns = `mvc`
            )->a( n = `xmlns`     v = `sap.m`
            )->a( n = `xmlns:mvc` v = `sap.ui.core.mvc`

            )->ele( `Page`
                )->a( n = `title` v = `Last night`

                )->ele( `Table`
                    )->a( n = `items` v = client->_bind( runs )

                    )->ele( `columns`
                        )->ele( `Column`
                            )->tag( `Text`
                                )->a( n = `text` v = `Job`
                        )->end(
                        )->ele( `Column`
                            )->tag( `Text`
                                )->a( n = `text` v = `Finished`
                        )->end(
                        )->ele( `Column`
                            )->tag( `Text`
                                )->a( n = `text` v = `State`
                        )->end(
                    )->end(

                    )->ele( `items`
                        )->ele( `ColumnListItem`
                            )->ele( `cells`
                                )->tag( `Text`
                                    )->a( n = `text` v = `{JOB}`
                                )->tag( `Text`
                                    )->a( n = `text` v = `{FINISH}`
                                )->tag( `ObjectStatus`
                                    )->a( n = `text`  v = `{STATE}`
                                    )->a( n = `state` v = `{STATE}` ).

    client->view_display( view->stringify( ) ).

  ENDMETHOD.

  METHOD model_init.
    runs = VALUE #( ( job = `ZFI_POSTING`  finish = `03:14`  state = `Success` )
                    ( job = `ZMM_REORG`    finish = `03:41`  state = `Warning` )
                    ( job = `ZSD_INVOICES` finish = `04:02`  state = `Error` ) ).
  ENDMETHOD.

ENDCLASS.

Activate it, call the ICF endpoint with ?app_start=zcl_job_monitor, and it is on screen. Replace model_init( ) with the SELECT that reads your job log and it is finished. Nothing published, nothing to deprecate.

What you pay instead: you write the view by hand. Nothing generates it from annotations, nothing gives you filter bars, variants or export for free. For the screens above that is a rounding error — a table and two buttons. For a list report with fifteen filters it is the wrong trade by a wide margin, and Fiori Elements will beat this by a distance.

Knowing which of the two you are looking at is most of the skill.

Happy ABAPing! 🦖🦕🦣