Wrapper-Klassen in ABAP Cloud: Classic APIs zugänglich machen

kategorie
ABAP Cloud
Veröffentlicht
autor
Johannes

Wrapper-Klassen sind ein zentrales Pattern in ABAP Cloud, um auf Funktionalität zuzugreifen, die nicht als Released API verfügbar ist. Dieser Artikel zeigt, wie du eigene Wrapper erstellst und dabei Best Practices einhältst.

Warum Wrapper-Klassen?

In ABAP Cloud gilt das strenge API-Konzept:

API-StatusNutzbar in ABAP CloudBeispiele
Released (C1)JaCL_SALV_TABLE, CL_HTTP_CLIENT
Not ReleasedNein (direkt)FM BAPI_*, klassische Reports
DeprecatedNeinVeraltete APIs

Das Problem

Viele bewährte Funktionen sind in ABAP Cloud nicht direkt nutzbar:

  • BAPI-Funktionsbausteine
  • Klassische Dynpro-Module
  • Nicht-released Klassen und Methoden
  • Legacy-Schnittstellen

Die Lösung: Wrapper

Ein Wrapper kapselt die nicht-released API und stellt sie als C1-released API bereit:

[ABAP Cloud Code] --> [Wrapper (C1)] --> [Non-Released API]

Released vs. Non-Released APIs

Prüfen des Release-Status

" In ADT: Rechtsklick auf Objekt -> Properties -> API State
" Oder programmatisch:
DATA(lo_api_state) = cl_oo_class=>get_instance( 'CL_HTTP_CLIENT' ).

Kennzeichnung in ADT

  • C1 (Released): Grünes Häkchen - für ABAP Cloud nutzbar
  • C0 (Not Released): Kein Symbol - nur On-Premise
  • Deprecated: Durchgestrichen - nicht mehr verwenden

Wrapper-Klasse erstellen

Schritt 1: Interface definieren

INTERFACE zif_number_range_wrapper
  PUBLIC.


  TYPES: BEGIN OF ty_number,
           number TYPE numc10,
         END OF ty_number.


  METHODS get_next_number
    IMPORTING
      iv_object    TYPE nrobj
      iv_subobject TYPE nrsobj OPTIONAL
    RETURNING
      VALUE(rs_number) TYPE ty_number
    RAISING
      cx_number_range_error.


ENDINTERFACE.

Schritt 2: Wrapper-Klasse implementieren

CLASS zcl_number_range_wrapper DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC.


  PUBLIC SECTION.
    INTERFACES zif_number_range_wrapper.


    ALIASES get_next_number FOR zif_number_range_wrapper~get_next_number.


  PRIVATE SECTION.
    METHODS call_number_get_next
      IMPORTING
        iv_object    TYPE nrobj
        iv_subobject TYPE nrsobj
      EXPORTING
        ev_number    TYPE numc10
      RAISING
        cx_number_range_error.


ENDCLASS.


CLASS zcl_number_range_wrapper IMPLEMENTATION.


  METHOD zif_number_range_wrapper~get_next_number.
    " Interner Aufruf der nicht-released API
    call_number_get_next(
      EXPORTING
        iv_object    = iv_object
        iv_subobject = COND #( WHEN iv_subobject IS INITIAL
                               THEN '01'
                               ELSE iv_subobject )
      IMPORTING
        ev_number = rs_number-number
    ).
  ENDMETHOD.


  METHOD call_number_get_next.
    " Aufruf des nicht-released Funktionsbausteins
    " Hinweis: Dies funktioniert nur On-Premise oder in
    " Embedded Steampunk, wenn der FB verfügbar ist
    DATA: lv_number TYPE numc10,
          lv_returncode TYPE char1.


    CALL FUNCTION 'NUMBER_GET_NEXT'
      EXPORTING
        nr_range_nr = '01'
        object      = iv_object
        subobject   = iv_subobject
      IMPORTING
        number      = lv_number
        returncode  = lv_returncode
      EXCEPTIONS
        OTHERS      = 1.


    IF sy-subrc <> 0.
      RAISE EXCEPTION TYPE cx_number_range_error
        EXPORTING
          textid = cx_number_range_error=>nr_not_found.
    ENDIF.


    ev_number = lv_number.
  ENDMETHOD.


ENDCLASS.

Schritt 3: C1-Release setzen

In ADT:

  1. Klasse öffnen
  2. Properties -> API State
  3. Release State: “Released” (C1)
  4. Visibility: “Use in Cloud Development”

Best Practices für Wrapper-Design

1. Klare Schnittstelle

" SCHLECHT: Alle Parameter durchreichen
METHODS call_bapi
  IMPORTING
    it_params TYPE any_table.


" GUT: Typisierte, minimale Schnittstelle
METHODS create_sales_order
  IMPORTING
    is_header TYPE zif_sales_order_api=>ty_header
    it_items  TYPE zif_sales_order_api=>tt_items
  RETURNING
    VALUE(rv_order_id) TYPE vbeln
  RAISING
    zcx_sales_order_error.

2. Keine internen Typen exponieren

CLASS zcl_material_wrapper DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC.


  PUBLIC SECTION.
    " GUT: Eigene Typen definieren
    TYPES: BEGIN OF ty_material,
             material_id   TYPE matnr,
             description   TYPE maktx,
             material_type TYPE mtart,
             base_unit     TYPE meins,
           END OF ty_material.


    METHODS get_material
      IMPORTING
        iv_material_id TYPE matnr
      RETURNING
        VALUE(rs_material) TYPE ty_material
      RAISING
        zcx_material_not_found.


  PRIVATE SECTION.
    " Interne Struktur für BAPI
    TYPES: BEGIN OF ty_bapi_material,
             matnr TYPE matnr,
             maktx TYPE maktx,
             mtart TYPE mtart,
             " ... viele weitere BAPI-Felder
           END OF ty_bapi_material.


ENDCLASS.


CLASS zcl_material_wrapper IMPLEMENTATION.


  METHOD get_material.
    DATA: ls_bapi_material TYPE ty_bapi_material.


    " BAPI aufrufen (non-released)
    CALL FUNCTION 'BAPI_MATERIAL_GET_DETAIL'
      EXPORTING
        material = iv_material_id
      IMPORTING
        material_general_data = ls_bapi_material
      EXCEPTIONS
        OTHERS = 1.


    IF sy-subrc <> 0.
      RAISE EXCEPTION TYPE zcx_material_not_found
        EXPORTING
          material_id = iv_material_id.
    ENDIF.


    " Mapping auf öffentliche Struktur
    rs_material = VALUE #(
      material_id   = ls_bapi_material-matnr
      description   = ls_bapi_material-maktx
      material_type = ls_bapi_material-mtart
      base_unit     = ls_bapi_material-meins
    ).
  ENDMETHOD.


ENDCLASS.

3. Stateless Design

" SCHLECHT: Zustand in der Klasse halten
CLASS zcl_bad_wrapper DEFINITION.
  PRIVATE SECTION.
    DATA: mv_current_order TYPE vbeln.
ENDCLASS.


" GUT: Alle Daten über Parameter übergeben
CLASS zcl_good_wrapper DEFINITION.
  PUBLIC SECTION.
    METHODS process_order
      IMPORTING
        iv_order_id TYPE vbeln
      RETURNING
        VALUE(rs_result) TYPE ty_result.
ENDCLASS.

Fehlerbehandlung in Wrappern

Exception-Klasse definieren

CLASS zcx_wrapper_error DEFINITION
  PUBLIC
  INHERITING FROM cx_static_check
  FINAL
  CREATE PUBLIC.


  PUBLIC SECTION.
    INTERFACES if_t100_message.
    INTERFACES if_t100_dyn_msg.


    CONSTANTS:
      BEGIN OF api_call_failed,
        msgid TYPE symsgid VALUE 'ZWRAPPER',
        msgno TYPE symsgno VALUE '001',
        attr1 TYPE scx_attrname VALUE 'MV_API_NAME',
        attr2 TYPE scx_attrname VALUE 'MV_ERROR_TEXT',
        attr3 TYPE scx_attrname VALUE '',
        attr4 TYPE scx_attrname VALUE '',
      END OF api_call_failed,


      BEGIN OF not_authorized,
        msgid TYPE symsgid VALUE 'ZWRAPPER',
        msgno TYPE symsgno VALUE '002',
        attr1 TYPE scx_attrname VALUE 'MV_OPERATION',
        attr2 TYPE scx_attrname VALUE '',
        attr3 TYPE scx_attrname VALUE '',
        attr4 TYPE scx_attrname VALUE '',
      END OF not_authorized.


    DATA: mv_api_name   TYPE string READ-ONLY,
          mv_error_text TYPE string READ-ONLY,
          mv_operation  TYPE string READ-ONLY.


    METHODS constructor
      IMPORTING
        textid     LIKE if_t100_message=>t100key OPTIONAL
        previous   LIKE previous OPTIONAL
        api_name   TYPE string OPTIONAL
        error_text TYPE string OPTIONAL
        operation  TYPE string OPTIONAL.


ENDCLASS.


CLASS zcx_wrapper_error IMPLEMENTATION.


  METHOD constructor.
    super->constructor( previous = previous ).
    mv_api_name = api_name.
    mv_error_text = error_text.
    mv_operation = operation.


    CLEAR me->textid.
    IF textid IS INITIAL.
      if_t100_message~t100key = if_t100_message=>default_textid.
    ELSE.
      if_t100_message~t100key = textid.
    ENDIF.
  ENDMETHOD.


ENDCLASS.

Fehler abfangen und transformieren

CLASS zcl_sales_order_wrapper IMPLEMENTATION.


  METHOD create_order.
    DATA: lt_return TYPE bapiret2_t.


    " BAPI aufrufen
    CALL FUNCTION 'BAPI_SALESORDER_CREATEFROMDAT2'
      EXPORTING
        order_header_in = is_header
      IMPORTING
        salesdocument   = rv_order_id
      TABLES
        order_items_in  = it_items
        return          = lt_return.


    " Fehler prüfen
    LOOP AT lt_return ASSIGNING FIELD-SYMBOL(<return>)
      WHERE type CA 'EA'.


      " Fehler in eigene Exception transformieren
      RAISE EXCEPTION TYPE zcx_wrapper_error
        EXPORTING
          textid     = zcx_wrapper_error=>api_call_failed
          api_name   = 'BAPI_SALESORDER_CREATEFROMDAT2'
          error_text = <return>-message.
    ENDLOOP.


    " Commit Work bei Erfolg
    IF rv_order_id IS NOT INITIAL.
      CALL FUNCTION 'BAPI_TRANSACTION_COMMIT'
        EXPORTING
          wait = abap_true.
    ENDIF.
  ENDMETHOD.


ENDCLASS.

Factory-Pattern für Wrapper

Für flexible Instanziierung und Testbarkeit:

CLASS zcl_wrapper_factory DEFINITION
  PUBLIC
  FINAL
  CREATE PRIVATE.


  PUBLIC SECTION.
    CLASS-METHODS get_instance
      RETURNING
        VALUE(ro_instance) TYPE REF TO zcl_wrapper_factory.


    METHODS get_number_range_wrapper
      RETURNING
        VALUE(ro_wrapper) TYPE REF TO zif_number_range_wrapper.


    METHODS get_material_wrapper
      RETURNING
        VALUE(ro_wrapper) TYPE REF TO zif_material_wrapper.


    " Für Unit Tests: Mocks injizieren
    METHODS set_mock_number_range
      IMPORTING
        io_mock TYPE REF TO zif_number_range_wrapper.


  PRIVATE SECTION.
    CLASS-DATA: go_instance TYPE REF TO zcl_wrapper_factory.
    DATA: mo_number_range_mock TYPE REF TO zif_number_range_wrapper.


ENDCLASS.


CLASS zcl_wrapper_factory IMPLEMENTATION.


  METHOD get_instance.
    IF go_instance IS NOT BOUND.
      go_instance = NEW #( ).
    ENDIF.
    ro_instance = go_instance.
  ENDMETHOD.


  METHOD get_number_range_wrapper.
    " Mock hat Vorrang (für Tests)
    IF mo_number_range_mock IS BOUND.
      ro_wrapper = mo_number_range_mock.
    ELSE.
      ro_wrapper = NEW zcl_number_range_wrapper( ).
    ENDIF.
  ENDMETHOD.


  METHOD get_material_wrapper.
    ro_wrapper = NEW zcl_material_wrapper( ).
  ENDMETHOD.


  METHOD set_mock_number_range.
    mo_number_range_mock = io_mock.
  ENDMETHOD.


ENDCLASS.

Nutzung in produktivem Code

CLASS zcl_booking_service IMPLEMENTATION.


  METHOD create_booking.
    " Wrapper über Factory holen
    DATA(lo_number_wrapper) = zcl_wrapper_factory=>get_instance(
      )->get_number_range_wrapper( ).


    " Nächste Buchungsnummer holen
    DATA(ls_number) = lo_number_wrapper->get_next_number(
      iv_object = 'ZBOOKING'
    ).


    rs_booking-booking_id = ls_number-number.
    " ... weitere Logik
  ENDMETHOD.


ENDCLASS.

Nutzung in Unit Tests

CLASS ltc_booking_service DEFINITION
  FOR TESTING
  DURATION SHORT
  RISK LEVEL HARMLESS.


  PRIVATE SECTION.
    DATA: mo_cut TYPE REF TO zcl_booking_service,
          mo_number_mock TYPE REF TO ltd_number_range_mock.


    METHODS setup.
    METHODS test_create_booking FOR TESTING.


ENDCLASS.


CLASS ltc_booking_service IMPLEMENTATION.


  METHOD setup.
    " Mock erstellen
    mo_number_mock = NEW #( ).
    mo_number_mock->set_next_number( '0000001234' ).


    " Mock injizieren
    zcl_wrapper_factory=>get_instance(
      )->set_mock_number_range( mo_number_mock ).


    mo_cut = NEW #( ).
  ENDMETHOD.


  METHOD test_create_booking.
    DATA(ls_booking) = mo_cut->create_booking( is_input ).


    cl_abap_unit_assert=>assert_equals(
      exp = '0000001234'
      act = ls_booking-booking_id
    ).
  ENDMETHOD.


ENDCLASS.

Wrapper vs. Alternativen

AnsatzVorteileNachteile
WrapperVolle Kontrolle, testbarAufwand, Wartung
Extension IncludeSAP-Standard nutzenEingeschränkt, nicht für alle APIs
Released API wartenKein eigener CodeUngewisse Verfügbarkeit
Side-by-Side ExtensionSauber getrenntBTP erforderlich

Checkliste für Wrapper

Vor dem Erstellen eines Wrappers prüfen:

  1. Gibt es eine Released API?

    • SAP API Business Hub durchsuchen
    • In ADT nach C1-Klassen suchen

  2. Ist der Wrapper wirklich nötig?

    • Kann die Funktionalität anders implementiert werden?
    • Gibt es einen moderneren Ansatz?

  3. Wrapper-Design planen:

    • Interface definiert
    • Eigene Typen (keine internen SAP-Typen exponieren)
    • Exception-Klasse mit sprechenden Fehlern
    • Factory für Testbarkeit
    • Stateless implementiert

  4. Dokumentation:

    • Welche non-released API wird gekapselt
    • Bekannte Einschränkungen
    • Upgrade-Pfad (falls SAP Released API bereitstellt)

Weiterführende Themen