Enumeraciones en ABAP: Tipos seguros para valores fijos

TYPES: BEGIN OF ENUM <nombre_enum> [ BASE TYPE <tipo_base> ] [ STRUCTURE <estructura> ],
         <valor1> [ VALUE <valor> ],
         <valor2> [ VALUE <valor> ],
         ...
       END OF ENUM <nombre_enum>.

TYPES: BEGIN OF ENUM ty_status,
         open,
         in_process,
         completed,
         cancelled,
       END OF ENUM ty_status.

DATA: lv_status TYPE ty_status.

lv_status = in_process.

IF lv_status = completed.
  WRITE: / 'El pedido esta completado'.
ENDIF.

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

DATA: lv_prio TYPE ty_priority.

lv_prio = priority-high.

CASE lv_prio.
  WHEN priority-low.
    WRITE: / 'Prioridad baja'.
  WHEN priority-medium.
    WRITE: / 'Prioridad media'.
  WHEN priority-high.
    WRITE: / 'Prioridad alta'.
  WHEN priority-critical.
    WRITE: / 'Prioridad critica!'.
ENDCASE.

TYPES: BEGIN OF ENUM ty_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.

DATA: lv_code TYPE ty_http_status.

lv_code = not_found.

WRITE: / 'Codigo HTTP:', lv_code.  " Salida: 404

TYPES: BEGIN OF ENUM ty_document_type BASE TYPE c LENGTH 2
                                       STRUCTURE doc_type,
         invoice     VALUE 'IV',
         credit_memo VALUE 'CM',
         debit_memo  VALUE 'DM',
         order       VALUE 'OR',
       END OF ENUM ty_document_type.

DATA: lv_type TYPE ty_document_type.

lv_type = doc_type-invoice.

WRITE: / 'Tipo de documento:', lv_type.  " Salida: IV

TYPES: BEGIN OF ENUM ty_approval_status STRUCTURE approval,
         undefined VALUE IS INITIAL,  " Este es el valor inicial!
         pending,
         approved,
         rejected,
       END OF ENUM ty_approval_status.

DATA: lv_approval TYPE ty_approval_status.

" lv_approval ya esta en 'undefined'
IF lv_approval = approval-undefined.
  WRITE: / 'El estado aun no esta establecido'.
ENDIF.

" CLEAR tambien establece a 'undefined'
lv_approval = approval-approved.
CLEAR lv_approval.
" lv_approval ahora es de nuevo 'undefined'

CLASS zcl_order DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    TYPES: BEGIN OF ENUM ty_order_status STRUCTURE status,
             draft,
             submitted,
             approved,
             rejected,
             completed,
           END OF ENUM ty_order_status.

    METHODS:
      constructor IMPORTING iv_id TYPE string,
      set_status IMPORTING iv_status TYPE ty_order_status,
      get_status RETURNING VALUE(rv_status) TYPE ty_order_status,
      get_status_text RETURNING VALUE(rv_text) TYPE string.

  PRIVATE SECTION.
    DATA: mv_id     TYPE string,
          mv_status TYPE ty_order_status.
ENDCLASS.

CLASS zcl_order IMPLEMENTATION.
  METHOD constructor.
    mv_id = iv_id.
    mv_status = status-draft.
  ENDMETHOD.

  METHOD set_status.
    mv_status = iv_status.
  ENDMETHOD.

  METHOD get_status.
    rv_status = mv_status.
  ENDMETHOD.

  METHOD get_status_text.
    rv_text = SWITCH #( mv_status
      WHEN status-draft     THEN 'Borrador'
      WHEN status-submitted THEN 'Enviado'
      WHEN status-approved  THEN 'Aprobado'
      WHEN status-rejected  THEN 'Rechazado'
      WHEN status-completed THEN 'Completado'
    ).
  ENDMETHOD.
ENDCLASS.

CLASS zcl_enum_helper DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    TYPES: BEGIN OF ENUM ty_color STRUCTURE color,
             red,
             green,
             blue,
             yellow,
           END OF ENUM ty_color.

    CLASS-METHODS:
      to_string
        IMPORTING iv_color        TYPE ty_color
        RETURNING VALUE(rv_string) TYPE string,

      from_string
        IMPORTING iv_string       TYPE string
        RETURNING VALUE(rv_color) TYPE ty_color
        RAISING   cx_sy_conversion_no_enum_value.
ENDCLASS.

CLASS zcl_enum_helper IMPLEMENTATION.
  METHOD to_string.
    rv_string = SWITCH #( iv_color
      WHEN color-red    THEN 'ROJO'
      WHEN color-green  THEN 'VERDE'
      WHEN color-blue   THEN 'AZUL'
      WHEN color-yellow THEN 'AMARILLO'
    ).
  ENDMETHOD.

  METHOD from_string.
    rv_color = SWITCH #( to_upper( iv_string )
      WHEN 'ROJO'     THEN color-red
      WHEN 'RED'      THEN color-red
      WHEN 'VERDE'    THEN color-green
      WHEN 'GREEN'    THEN color-green
      WHEN 'AZUL'     THEN color-blue
      WHEN 'BLUE'     THEN color-blue
      WHEN 'AMARILLO' THEN color-yellow
      WHEN 'YELLOW'   THEN color-yellow
      ELSE THROW cx_sy_conversion_no_enum_value( )
    ).
  ENDMETHOD.
ENDCLASS.

CLASS zcl_workflow DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    TYPES: BEGIN OF ENUM ty_state STRUCTURE state,
             initial VALUE IS INITIAL,
             created,
             submitted,
             in_review,
             approved,
             rejected,
             archived,
           END OF ENUM ty_state.

    METHODS:
      transition
        IMPORTING iv_new_state TYPE ty_state
        RAISING   zcx_invalid_transition,
      get_allowed_transitions
        RETURNING VALUE(rt_states) TYPE STANDARD TABLE OF ty_state
                                   WITH EMPTY KEY.

  PRIVATE SECTION.
    DATA: mv_current_state TYPE ty_state.

    METHODS is_valid_transition
      IMPORTING iv_from          TYPE ty_state
                iv_to            TYPE ty_state
      RETURNING VALUE(rv_valid) TYPE abap_bool.
ENDCLASS.

CLASS zcl_workflow IMPLEMENTATION.
  METHOD is_valid_transition.
    " Definir transiciones validas
    rv_valid = abap_false.

    CASE iv_from.
      WHEN state-initial.
        rv_valid = xsdbool( iv_to = state-created ).

      WHEN state-created.
        rv_valid = xsdbool( iv_to = state-submitted ).

      WHEN state-submitted.
        rv_valid = xsdbool( iv_to = state-in_review OR
                            iv_to = state-rejected ).

      WHEN state-in_review.
        rv_valid = xsdbool( iv_to = state-approved OR
                            iv_to = state-rejected ).

      WHEN state-approved.
        rv_valid = xsdbool( iv_to = state-archived ).

      WHEN state-rejected.
        rv_valid = xsdbool( iv_to = state-archived OR
                            iv_to = state-created ).
    ENDCASE.
  ENDMETHOD.

  METHOD transition.
    IF NOT is_valid_transition( iv_from = mv_current_state
                                iv_to   = iv_new_state ).
      RAISE EXCEPTION TYPE zcx_invalid_transition.
    ENDIF.

    mv_current_state = iv_new_state.
  ENDMETHOD.

  METHOD get_allowed_transitions.
    " Devolver todas las transiciones validas desde el estado actual
    DATA(lt_all_states) = VALUE STANDARD TABLE OF ty_state(
      ( state-initial )
      ( state-created )
      ( state-submitted )
      ( state-in_review )
      ( state-approved )
      ( state-rejected )
      ( state-archived )
    ).

    LOOP AT lt_all_states INTO DATA(lv_state).
      IF is_valid_transition( iv_from = mv_current_state
                              iv_to   = lv_state ).
        APPEND lv_state TO rt_states.
      ENDIF.
    ENDLOOP.
  ENDMETHOD.
ENDCLASS.

@EndUserText.label: 'Estado del Pedido'
define type ZDE_OrderStatus : abap.char(1) enum {
  Open      = 'O';
  InProcess = 'P';
  Completed = 'C';
  Cancelled = 'X';
}

define view entity ZI_Order as select from zorder {
  key order_id,
      @ObjectModel.text.element: ['StatusText']
      cast(status as ZDE_OrderStatus) as Status,
      case status
        when 'O' then 'Abierto'
        when 'P' then 'En Proceso'
        when 'C' then 'Completado'
        when 'X' then 'Cancelado'
      end as StatusText
}

TYPES: BEGIN OF ENUM ty_level STRUCTURE level,
         beginner,    " = 0
         intermediate," = 1
         advanced,    " = 2
         expert,      " = 3
       END OF ENUM ty_level.

DATA: lv_level TYPE ty_level,
      lv_int   TYPE i.

" Enum a Integer
lv_level = level-advanced.
lv_int = CONV #( lv_level ).  " = 2

" Integer a Enum (con CONV)
lv_int = 1.
lv_level = CONV #( lv_int ).  " = intermediate

" Error si el valor esta fuera de rango!
TRY.
    lv_int = 99.
    lv_level = CONV #( lv_int ).
  CATCH cx_sy_conversion_no_enum_value.
    WRITE: / 'Valor de enum invalido'.
ENDTRY.