ABAP Enumerations: Typsichere Aufzählungen

TYPES: BEGIN OF ENUM <enum_name> [ BASE TYPE <basistyp> ] [ STRUCTURE <struktur_name> ],
         <wert1> [ VALUE <n> ],
         <wert2> [ VALUE <n> ],
         ...
       END OF ENUM <enum_name> [ STRUCTURE <struktur_name> ].

" Enumeration definieren
TYPES: BEGIN OF ENUM ty_traffic_light,
         red,
         yellow,
         green,
       END OF ENUM ty_traffic_light.

" Variable deklarieren
DATA: lv_light TYPE ty_traffic_light.

" Wert zuweisen
lv_light = red.

" In Bedingungen verwenden
CASE lv_light.
  WHEN red.
    WRITE: / 'Stop!'.
  WHEN yellow.
    WRITE: / 'Achtung!'.
  WHEN green.
    WRITE: / 'Fahren!'.
ENDCASE.

" === ALT: Lose Konstanten (fehleranfällig) ===
CONSTANTS: c_status_new       TYPE c VALUE 'N',
           c_status_approved  TYPE c VALUE 'A',
           c_status_rejected  TYPE c VALUE 'R'.

DATA: lv_status TYPE c.
lv_status = 'X'.  " Ungültiger Wert - kein Compilerfehler!


" === NEU: Enumeration (typsicher) ===
TYPES: BEGIN OF ENUM ty_status,
         new,
         approved,
         rejected,
       END OF ENUM ty_status.

DATA: lv_status2 TYPE ty_status.
lv_status2 = approved.   " OK
" lv_status2 = 'X'.      " SYNTAXFEHLER! Nur Enum-Werte erlaubt

" Mit STRUCTURE für qualifizierten Zugriff
TYPES: BEGIN OF ENUM ty_order_status STRUCTURE order_status,
         open,
         processing,
         shipped,
         delivered,
         cancelled,
       END OF ENUM ty_order_status STRUCTURE order_status.

DATA: lv_status TYPE ty_order_status.

" Qualifizierter Zugriff über Struktur
lv_status = order_status-processing.

CASE lv_status.
  WHEN order_status-open.
    WRITE: / 'Bestellung offen'.
  WHEN order_status-processing.
    WRITE: / 'In Bearbeitung'.
  WHEN order_status-shipped.
    WRITE: / 'Versandt'.
  WHEN order_status-delivered.
    WRITE: / 'Geliefert'.
  WHEN order_status-cancelled.
    WRITE: / 'Storniert'.
ENDCASE.

" Standard: Automatische Werte 0, 1, 2, ...
TYPES: BEGIN OF ENUM ty_auto,
         val_a,    " = 0
         val_b,    " = 1
         val_c,    " = 2
       END OF ENUM ty_auto.

" Explizite Werte zuweisen
TYPES: BEGIN OF ENUM ty_http_status STRUCTURE http_status BASE TYPE i,
         ok            VALUE 200,
         created       VALUE 201,
         bad_request   VALUE 400,
         unauthorized  VALUE 401,
         not_found     VALUE 404,
         server_error  VALUE 500,
       END OF ENUM ty_http_status STRUCTURE http_status.

DATA: lv_http TYPE ty_http_status.
lv_http = http_status-not_found.

WRITE: / 'HTTP Status:', CONV i( lv_http ).  " 404

" String-basierte Enumeration
TYPES: BEGIN OF ENUM ty_color STRUCTURE color BASE TYPE string,
         red    VALUE `#FF0000`,
         green  VALUE `#00FF00`,
         blue   VALUE `#0000FF`,
         white  VALUE `#FFFFFF`,
         black  VALUE `#000000`,
       END OF ENUM ty_color STRUCTURE color.

DATA: lv_color TYPE ty_color.
lv_color = color-blue.

" Wert extrahieren
DATA(lv_hex) = CONV string( lv_color ).
WRITE: / 'Farbcode:', lv_hex.  " #0000FF

CLASS lcl_order DEFINITION.
  PUBLIC SECTION.
    " Enumeration als Klassentyp
    TYPES: BEGIN OF ENUM ty_status STRUCTURE status,
             draft,
             submitted,
             approved,
             rejected,
           END OF ENUM ty_status STRUCTURE status.

    METHODS: constructor,
             set_status IMPORTING iv_status TYPE ty_status,
             get_status RETURNING VALUE(rv_status) TYPE ty_status,
             approve,
             reject.

  PRIVATE SECTION.
    DATA: mv_status TYPE ty_status.
ENDCLASS.

CLASS lcl_order IMPLEMENTATION.
  METHOD constructor.
    mv_status = status-draft.
  ENDMETHOD.

  METHOD set_status.
    mv_status = iv_status.
  ENDMETHOD.

  METHOD get_status.
    rv_status = mv_status.
  ENDMETHOD.

  METHOD approve.
    IF mv_status = status-submitted.
      mv_status = status-approved.
    ENDIF.
  ENDMETHOD.

  METHOD reject.
    IF mv_status = status-submitted.
      mv_status = status-rejected.
    ENDIF.
  ENDMETHOD.
ENDCLASS.


" Verwendung
DATA(lo_order) = NEW lcl_order( ).

lo_order->set_status( lcl_order=>status-submitted ).
lo_order->approve( ).

DATA(lv_current) = lo_order->get_status( ).
IF lv_current = lcl_order=>status-approved.
  WRITE: / 'Bestellung genehmigt'.
ENDIF.

TYPES: BEGIN OF ENUM ty_weekday STRUCTURE weekday,
         monday,
         tuesday,
         wednesday,
         thursday,
         friday,
         saturday,
         sunday,
       END OF ENUM ty_weekday STRUCTURE weekday.

DATA: lv_day TYPE ty_weekday VALUE weekday-friday.

" Mit SWITCH
DATA(lv_type) = SWITCH string( lv_day
  WHEN weekday-saturday OR weekday-sunday THEN 'Wochenende'
  ELSE 'Werktag'
).

" Mit COND
DATA(lv_message) = COND string(
  WHEN lv_day = weekday-monday THEN 'Wochenstart'
  WHEN lv_day = weekday-friday THEN 'Fast Wochenende!'
  WHEN lv_day = weekday-saturday OR lv_day = weekday-sunday THEN 'Frei!'
  ELSE 'Normaler Tag'
).

WRITE: / lv_type.     " Werktag
WRITE: / lv_message.  " Fast Wochenende!

TYPES: BEGIN OF ENUM ty_priority STRUCTURE priority,
         low,
         medium,
         high,
         critical,
       END OF ENUM ty_priority STRUCTURE priority.

TYPES: BEGIN OF ty_task,
         id       TYPE i,
         name     TYPE string,
         priority TYPE ty_priority,
       END OF ty_task.

" Struktur mit Enumeration initialisieren
DATA(ls_task) = VALUE ty_task(
  id       = 1
  name     = 'Wichtige Aufgabe'
  priority = priority-high
).

" Tabelle mit Enumerations
DATA: lt_tasks TYPE TABLE OF ty_task.

lt_tasks = VALUE #(
  ( id = 1 name = 'Bug Fix'  priority = priority-critical )
  ( id = 2 name = 'Feature'  priority = priority-medium )
  ( id = 3 name = 'Doku'     priority = priority-low )
).

" Filtern nach Priorität
LOOP AT lt_tasks INTO DATA(ls_t) WHERE priority >= priority-high.
  WRITE: / ls_t-id, ls_t-name.
ENDLOOP.

TYPES: BEGIN OF ENUM ty_size STRUCTURE size,
         xs,
         s,
         m,
         l,
         xl,
         xxl,
       END OF ENUM ty_size STRUCTURE size.

" Alle Werte durchlaufen (mit Integer-Konvertierung)
DO.
  DATA(lv_size) = CONV ty_size( sy-index - 1 ).

  " Prüfen ob gültiger Wert (innerhalb des Bereichs)
  IF lv_size > size-xxl.
    EXIT.
  ENDIF.

  WRITE: / 'Größe:', lv_size.
ENDDO.

INTERFACE lif_document.
  TYPES: BEGIN OF ENUM ty_doc_type STRUCTURE doc_type,
           invoice,
           credit_memo,
           delivery_note,
           quotation,
         END OF ENUM ty_doc_type STRUCTURE doc_type.

  METHODS: get_type RETURNING VALUE(rv_type) TYPE ty_doc_type.
ENDINTERFACE.


CLASS lcl_invoice DEFINITION.
  PUBLIC SECTION.
    INTERFACES: lif_document.
ENDCLASS.

CLASS lcl_invoice IMPLEMENTATION.
  METHOD lif_document~get_type.
    rv_type = lif_document=>doc_type-invoice.
  ENDMETHOD.
ENDCLASS.

TYPES: BEGIN OF ENUM ty_payment STRUCTURE payment,
         cash,
         credit_card,
         bank_transfer,
         paypal,
       END OF ENUM ty_payment STRUCTURE payment.

DATA: lv_payment TYPE ty_payment VALUE payment-credit_card.

" Enum-Name als String (Reflection)
DATA(lo_type) = CAST cl_abap_enumdescr(
  cl_abap_typedescr=>describe_by_data( lv_payment )
).

" Alle Members mit Namen
LOOP AT lo_type->members INTO DATA(ls_member).
  WRITE: / ls_member-name, '=', ls_member-value.
ENDLOOP.

" Ausgabe:
" CASH = 0
" CREDIT_CARD = 1
" BANK_TRANSFER = 2
" PAYPAL = 3

CLASS lcl_document_workflow DEFINITION.
  PUBLIC SECTION.
    TYPES: BEGIN OF ENUM ty_state STRUCTURE state,
             draft,
             pending_review,
             approved,
             published,
             archived,
           END OF ENUM ty_state STRUCTURE state.

    METHODS: constructor,
             submit RETURNING VALUE(rv_success) TYPE abap_bool,
             approve RETURNING VALUE(rv_success) TYPE abap_bool,
             publish RETURNING VALUE(rv_success) TYPE abap_bool,
             archive RETURNING VALUE(rv_success) TYPE abap_bool,
             get_state RETURNING VALUE(rv_state) TYPE ty_state,
             get_available_actions RETURNING VALUE(rt_actions) TYPE string_table.

  PRIVATE SECTION.
    DATA: mv_state TYPE ty_state.
ENDCLASS.

CLASS lcl_document_workflow IMPLEMENTATION.
  METHOD constructor.
    mv_state = state-draft.
  ENDMETHOD.

  METHOD submit.
    IF mv_state = state-draft.
      mv_state = state-pending_review.
      rv_success = abap_true.
    ENDIF.
  ENDMETHOD.

  METHOD approve.
    IF mv_state = state-pending_review.
      mv_state = state-approved.
      rv_success = abap_true.
    ENDIF.
  ENDMETHOD.

  METHOD publish.
    IF mv_state = state-approved.
      mv_state = state-published.
      rv_success = abap_true.
    ENDIF.
  ENDMETHOD.

  METHOD archive.
    IF mv_state = state-published.
      mv_state = state-archived.
      rv_success = abap_true.
    ENDIF.
  ENDMETHOD.

  METHOD get_state.
    rv_state = mv_state.
  ENDMETHOD.

  METHOD get_available_actions.
    rt_actions = SWITCH #( mv_state
      WHEN state-draft          THEN VALUE #( ( `Submit` ) )
      WHEN state-pending_review THEN VALUE #( ( `Approve` ) ( `Reject` ) )
      WHEN state-approved       THEN VALUE #( ( `Publish` ) )
      WHEN state-published      THEN VALUE #( ( `Archive` ) )
      ELSE VALUE #( )
    ).
  ENDMETHOD.
ENDCLASS.