Clean Core Strategie für S/4HANA: Der komplette Leitfaden

" ❌ SCHLECHT: Direkter Eingriff in SAP-Standard
ENHANCEMENT-POINT ep_vbap_check IN PROGRAM sapmv45a.
  " Kundeneigene Logik direkt im SAP-Standardprogramm
  IF vbap-matnr = 'SPECIAL'.
    vbap-kwmeng = vbap-kwmeng * 2.
  ENDIF.
END-ENHANCEMENT-POINT.

" ❌ SCHLECHT: Nicht-freigegebene Tabellen/Felder nutzen
SELECT SINGLE * FROM but000 WHERE partner = lv_partner.
" but000 ist nicht freigegeben → kann jederzeit ändern!

" ❌ SCHLECHT: User-Exits/BADIs mit unsauberem Zugriff
METHOD if_ex_badi_name~execute.
  " Direkter Zugriff auf interne SAP-Strukturen
  DATA(lv_internal) = cl_sap_internal_class=>get_data( ).
ENDMETHOD.

┌──────────────────────────────────────────────────────┐
│                   SAP Standard                        │
│              (SAP S/4HANA Core)                       │
│                                                       │
│  ┌─────────────────────────────────────────┐         │
│  │    Released APIs & Extension Points     │         │
│  │  (Von SAP garantiert stabil)             │         │
│  └──────────────┬──────────────────────────┘         │
└─────────────────┼───────────────────────────────────┘
                  │
                  │ Nur über freigegebene Schnittstellen
                  │
       ┌──────────▼──────────────────────────┐
       │     Clean Core Extensions           │
       │                                      │
       │  • Tier-3: In-Stack (ABAP Cloud)    │
       │  • Key User Extensibility           │
       │  • Side-by-Side (BTP)               │
       │  • API-Integration                  │
       └─────────────────────────────────────┘

" Auf BTP ABAP Environment entwickelt
CLASS zcl_btp_sales_extension DEFINITION PUBLIC.
  PUBLIC SECTION.
    INTERFACES if_oo_adt_classrun.
ENDCLASS.

CLASS zcl_btp_sales_extension IMPLEMENTATION.
  METHOD if_oo_adt_classrun~main.
    " Zugriff auf S/4HANA via OData/APIs
    DATA(lo_http) = cl_web_http_client_manager=>create_by_http_destination(
      i_destination = cl_http_destination_provider=>create_by_url(
        i_url = 'https://my-s4hana.com/sap/opu/odata4/sap/api_salesorder_v1' )
    ).

    DATA(lo_request) = lo_http->get_http_request( ).
    lo_request->set_header_field( i_name = 'Accept' i_value = 'application/json' ).

    DATA(lo_response) = lo_http->execute( if_web_http_client=>get ).
    DATA(lv_json) = lo_response->get_text( ).

    " Eigene Geschäftslogik
    " → Kein Zugriff auf S/4HANA-Interna
    " → Vollständig isoliert
  ENDMETHOD.
ENDCLASS.

SAP GUI → Einstellungen → Custom Fields and Logic
1. Objekt wählen (z.B. Sales Order)
2. "Neues Feld erstellen"
3. Feldname: ZZ_PRIORITY
4. Datentyp: String(10)
5. Auf UI hinzufügen
→ Fertig! Feld ist in Tabelle, CDS Views und UI verfügbar

1. Trigger wählen: "Before Save - Sales Order"
2. Bedingung: IF NetAmount > 10000
3. Aktion: SET ZZ_PRIORITY = 'HIGH'
→ Keine ABAP-Kenntnis nötig!

" ✅ GUT: ABAP Cloud Extension in S/4HANA
" Nur freigegebene APIs nutzen
CLASS zcl_sales_validator DEFINITION PUBLIC.
  PUBLIC SECTION.
    INTERFACES if_badi_interface.
ENDCLASS.

CLASS zcl_sales_validator IMPLEMENTATION.
  METHOD if_badi_interface~validate.
    " Zugriff NUR über Released APIs
    SELECT SINGLE *
      FROM i_salesorder  " ← Released CDS View (von SAP freigegeben)
      WHERE salesorder = @iv_order_id
      INTO @DATA(ls_order).

    " Geschäftslogik
    IF ls_order-TotalNetAmount > 50000.
      " Nachricht via Released API
      DATA(lo_msg) = cl_message_helper=>get_instance( ).  " ← Released
      lo_msg->add_message(
        id     = 'ZMSG'
        number = '001'
        v1     = 'Genehmigung erforderlich'
      ).
    ENDIF.
  ENDMETHOD.
ENDCLASS.

" In Eclipse ADT:
" 1. API öffnen (z.B. CDS View, Klasse)
" 2. Properties anzeigen → "API State"
" 3. Suchen nach "Released" oder "C1" (Cloud-Ready)

" Beispiel: I_SalesOrder
@AccessControl.authorizationCheck: #CHECK
@EndUserText.label: 'Sales Order'
@Metadata.allowExtensions: true
@ObjectModel.usageType.serviceQuality: #A
@VDM.viewType: #BASIC

" → Wenn @VDM.viewType vorhanden: Teil des Virtual Data Model (VDM)
"    = Released für Consumption!

define view I_SalesOrder
  as select from vbak  " ← vbak ist NICHT released, aber I_SalesOrder schon!
{
  key vbeln as SalesOrder,
      erdat as CreationDate,
      netwr as TotalNetAmount,
      waerk as TransactionCurrency
}

Filter: "API Type" → "ABAP Cloud"
        "Product" → "SAP S/4HANA"

Beispiele:
- I_SalesOrder, I_Customer, I_Product (CDS Views)
- CL_BALI_LOG (Application Logging)
- CL_NUMBERRANGE_RUNTIME (Number Ranges)
- CL_WEB_HTTP_* (HTTP Client)

" Transaktion: ATC (ABAP Test Cockpit)
" Oder in Eclipse ADT:
" Projekt → Properties → ABAP Development → Code Inspector

" Check Variant: S4HANA_READINESS_REMOTE
" → Zeigt alle Verwendungen nicht-freigegebener APIs

" ❌ Vorher: Nicht-released
SELECT SINGLE * FROM but000 WHERE partner = @lv_partner.

" ✅ Nachher: Released API
SELECT SINGLE * FROM i_businesspartner
  WHERE businesspartner = @lv_partner
  INTO @DATA(ls_bp).

" Zentraler Wrapper für kritische Zugriffe
CLASS zcl_bp_access DEFINITION PUBLIC CREATE PRIVATE.
  PUBLIC SECTION.
    CLASS-METHODS:
      get_instance RETURNING VALUE(ro_instance) TYPE REF TO zcl_bp_access,

      get_business_partner
        IMPORTING iv_partner        TYPE bu_partner
        RETURNING VALUE(rs_partner) TYPE i_businesspartner.

  PRIVATE SECTION.
    CLASS-DATA go_instance TYPE REF TO zcl_bp_access.
ENDCLASS.

CLASS zcl_bp_access IMPLEMENTATION.
  METHOD get_instance.
    IF go_instance IS NOT BOUND.
      CREATE OBJECT go_instance.
    ENDIF.
    ro_instance = go_instance.
  ENDMETHOD.

  METHOD get_business_partner.
    " Heute: Released API
    SELECT SINGLE * FROM i_businesspartner
      WHERE businesspartner = @iv_partner
      INTO @rs_partner.

    " Falls API nicht ausreicht:
    " TODO: SAP um API-Erweiterung bitten (über Influence Request)
  ENDMETHOD.
ENDCLASS.

" In Custom-Code überall:
DATA(ls_bp) = zcl_bp_access=>get_instance( )->get_business_partner( lv_partner ).
" → Wenn SAP API ändert: nur zcl_bp_access anpassen, nicht 100 Stellen

" ❌ Vorher: Dynpro-Programm mit DB-Direktzugriff
REPORT zsales_order_maintain.

PARAMETERS: p_order TYPE vbeln.

START-OF-SELECTION.
  " Direkte Tabellenzugriffe
  UPDATE vbak SET status = 'CLOSED' WHERE vbeln = p_order.
  COMMIT WORK.

" ✅ Nachher: RAP Business Object
" → siehe /rap-basics/ für Details
MODIFY ENTITIES OF i_salesordertp
  ENTITY SalesOrder
    UPDATE FIELDS ( OverallSDProcessStatus )
    WITH VALUE #( ( SalesOrder = lv_order
                    OverallSDProcessStatus = 'C' ) )
  FAILED DATA(failed)
  REPORTED DATA(reported).

COMMIT ENTITIES.

# Azure DevOps / Jenkins Pipeline
- task: ABAP_ATC_Check
  inputs:
    checkVariant: 'CUSTOM_CLOUD_READINESS'
    failOnErrors: true
    excludePackages: '$TMP'  # Testentwicklungen ausschließen

# ABAP Development Standards (Beispiel)

## Pflicht-Regeln
1. ✅ Nur Released APIs (Check: API Business Hub)
2. ✅ ABAP Cloud Syntax (kein CALL TRANSACTION, etc.)
3. ✅ RAP für transaktionale Apps (kein Dynpro)
4. ✅ CDS Views statt SELECT auf DB-Tabellen
5. ✅ Kein Implicit Enhancement Framework

## Empfehlungen
- Wrapper-Klassen für häufig genutzte APIs
- Unit Tests mit Test Doubles (siehe /test-doubles-mocking/)
- EML für BO-Zugriff (siehe /eml-guide/)

Pull Request Checklist:
□ ATC-Check grün (Clean Core Variant)?
□ Nur Released APIs verwendet?
□ Unit Tests vorhanden (Coverage ≥ 80%)?
□ CDS Views dokumentiert (Labels/Descriptions)?
□ Keine Implicit Enhancements?

" ABAP Cloud Language Version: Compiler erzwingt Clean Core!

CLASS zcl_order_processor DEFINITION PUBLIC.
  PUBLIC SECTION.
    INTERFACES if_oo_adt_classrun.
ENDCLASS.

CLASS zcl_order_processor IMPLEMENTATION.
  METHOD if_oo_adt_classrun~main.
    " ✅ Erlaubt: Released API
    SELECT * FROM i_salesorder
      INTO TABLE @DATA(lt_orders).

    " ❌ Compiler-Fehler: vbak ist nicht released!
    " SELECT * FROM vbak INTO TABLE @DATA(lt_vbak).
    " → "vbak is not released for ABAP Cloud"

    " ❌ Compiler-Fehler: CALL TRANSACTION nicht erlaubt
    " CALL TRANSACTION 'VA03'.
    " → "CALL TRANSACTION is not allowed in ABAP Cloud"
  ENDMETHOD.
ENDCLASS.

Eclipse ADT:
1. Package erstellen/öffnen
2. Properties → ABAP Language Version
3. Auswählen: "ABAP for Cloud Development"
→ Alle Objekte in diesem Package sind Clean Core-konform!

" ❌ User-Exit in SAP Standard eingebaut
ENHANCEMENT-SECTION zenhancement_vbap IN sapmv45a.
  ENHANCEMENT 1 zorder_validation.
    " Zugriff auf globale Variablen des SAP-Programms
    IF vbap-matnr CO '0123456789'.
      MESSAGE 'Ungültige Materialnummer' TYPE 'E'.
    ENDIF.
  ENDENHANCEMENT.
END-ENHANCEMENT-SECTION.

" ✅ Schritt 1: BAdI nutzen (falls vorhanden)
CLASS zcl_order_badi DEFINITION PUBLIC.
  PUBLIC SECTION.
    INTERFACES if_ex_sd_sales_item_check.  " ← SAP-BAdI
ENDCLASS.

CLASS zcl_order_badi IMPLEMENTATION.
  METHOD if_ex_sd_sales_item_check~validate_item.
    " Zugriff nur über Interface-Parameter (kein Global Access)
    IF is_item-material CO '0123456789'.
      " Released API für Messages
      DATA(lo_msg) = cl_bali_message_setter=>create(
        severity = if_bali_constants=>c_severity_error
        id       = 'ZMSG'
        number   = '001'
      ).
      APPEND lo_msg TO ct_messages.
    ENDIF.
  ENDMETHOD.
ENDCLASS.

" ✅ Schritt 2: Falls kein BAdI → Wrapper Event
" Siehe RAP Business Events: /events-raise-handler/

" ✅ Schritt 3: Langfristig → RAP Validation
" In Behavior Definition:
validation validateMaterialNumber on save
  { field Material; }

" Behavior Implementation:
METHOD validateMaterialNumber.
  READ ENTITIES OF zi_salesorder IN LOCAL MODE
    ENTITY SalesOrderItem
      FIELDS ( Material )
      WITH CORRESPONDING #( keys )
    RESULT DATA(lt_items).

  LOOP AT lt_items INTO DATA(ls_item) WHERE Material CO '0123456789'.
    APPEND VALUE #(
      %tky = ls_item-%tky
      %element-Material = if_abap_behv=>mk-on
    ) TO failed-salesorderitem.

    APPEND VALUE #(
      %tky = ls_item-%tky
      %msg = new_message_with_text(
        severity = if_abap_behv_message=>severity-error
        text     = 'Ungültige Materialnummer'
      )
    ) TO reported-salesorderitem.
  ENDLOOP.
ENDMETHOD.