Creación Modelo OO

[akiestudio]

Buenos días,
Estoy intentando crear un modelo orientando a objetos, tengo una class abstracta y otra clase de tabla.
Clase Abstracta.

class ZCL_MODEL_ABSTRACT definition
  public
  abstract
  create public .

public section.

  methods CALL_ALL_GETTERS
  final
    importing
      !TABLE type ref to DATA
      !TABLE_NAME type C optional
      !MODEL type ref to ZCL_GW_MODEL optional
    raising
      ZCX_DEMO_BO .
protected section.

  class-methods RAISE_EXCEPTION_ON_ERROR
    importing
      !BAPIRETURN type BAPIRET2_TAB optional
    raising
      ZCX_DEMO_BO .
  PRIVATE SECTION.

ENDCLASS.



CLASS ZCL_MODEL_ABSTRACT IMPLEMENTATION.


    METHOD CALL_ALL_GETTERS.
      DATA: struct_descr TYPE REF TO cl_abap_structdescr,
          parameter    TYPE abap_parmbind,
          parameters   TYPE abap_parmbind_tab.

      ASSIGN table->* TO FIELD-SYMBOL(<table>).
      CHECK sy-subrc = 0.

* ... otherwise we use RTTS to determine ABAP field names from entity itself.
      TRY.
*          struct_descr ?= cl_abap_structdescr=>describe_by_data_ref( table ).
           struct_descr ?= cl_abap_structdescr=>describe_by_name( TABLE_NAME ).
          LOOP AT struct_descr->components REFERENCE INTO DATA(component).
            CLEAR parameters.
            TRY.
                ASSIGN COMPONENT component->name OF STRUCTURE <table> TO FIELD-SYMBOL(<comp>).
                IF sy-subrc = 0.
                  parameter-name = component->name.
                  parameter-kind = cl_abap_objectdescr=>returning.
                  GET REFERENCE OF <comp> INTO parameter-value.
                  INSERT parameter INTO TABLE parameters.
                  DATA(method_name) = |GET_{ component->name }|.
                  CALL METHOD me->(method_name)
                    PARAMETER-TABLE parameters.
                ENDIF.
              CATCH cx_sy_dyn_call_error.
            ENDTRY.
          ENDLOOP.
           CATCH cx_root.
      ENDTRY.
	
  ENDMETHOD.

  METHOD raise_exception_on_error.
  LOOP AT bapireturn REFERENCE INTO DATA(lr_return) WHERE type = 'E'.
    MESSAGE ID lr_return->id TYPE lr_return->type NUMBER lr_return->number
            INTO DATA(error_message)
            WITH lr_return->message_v1 lr_return->message_v2 lr_return->message_v3 lr_return->message_v4.
    RAISE EXCEPTION TYPE zcx_demo_bo
      EXPORTING
        textid        = zcx_demo_bo=>error
        error_message = error_message.
  ENDLOOP.

ENDMETHOD.
ENDCLASS.

Clase de tabla.

class ZCL_MODEL_KNA1 definition
  public
  inheriting from ZCL_MODEL_ABSTRACT
  create protected .

public section.

  methods CONSTRUCTOR
    raising
      ZCX_DEMO_BO .
  methods MAP_TO_TABLE
    importing
      !TABLE type ref to DATA optional
      !TABLE_NAME type C optional
      !MODEL type ref to ZCL_GW_MODEL optional
    raising
      ZCX_DEMO_BO .
  class-methods GET
    returning
      value(INSTANCE) type ref to ZCL_MODEL_KNA1 .
  methods GET_KUNNR
    returning
      value(KUNNR) type KUNNR
    raising
      ZCX_DEMO_BO .
protected section.
   METHODS load_kna1_data
   RAISING
      zcx_demo_bo .
    
private section.
   DATA KNA1_DATA TYPE KNA1.
   class-DATA lo_instances TYPE REF TO ZCL_MODEL_KNA1 .


ENDCLASS.



CLASS ZCL_MODEL_KNA1 IMPLEMENTATION.


  METHOD CONSTRUCTOR.
    super->constructor( ).
    load_kna1_data(  ).

  ENDMETHOD.


 METHOD get.



    IF lo_instances IS INITIAL.
*     creation of the object
      CREATE OBJECT lo_instances.
    ENDIF.
*   assigning reference back to exporting parameter
    instance = lo_instances.



  ENDMETHOD.

  method GET_KUNNR.
    KUNNR = me->KNA1_DATA-KUNNR.
  endmethod.


  METHOD load_kna1_data.

    SELECT SINGLE *
      FROM kna1 AS ka
      INTO CORRESPONDING FIELDS OF @ME->KNA1_DATA.

    IF sy-subrc NE 0.
      RAISE EXCEPTION TYPE zcx_demo_bo
        EXPORTING
          textid  = zcx_demo_bo=>not_found
          bo_type = 'MODEL_KNA1'.
   ENDIF.
 ENDMETHOD.


   METHOD MAP_TO_TABLE.

    CALL_ALL_GETTERS(
       EXPORTING
         TABLE = TABLE
         TABLE_NAME  = TABLE_NAME
         model = model
         ).

  ENDMETHOD.
ENDCLASS.

Cuando intento llamarla en el programa,

data lo_mkna1 type REF TO ZCL_MODEL_KNA1.
data lt_mkna1 type STANDARD TABLE OF kna1.
data lr_mkna1 type REF TO data.
data io_model type REF TO zcl_gw_model.

lo_mkna1 = ZCL_MODEL_KNA1=>GET( ).


IO_MODEL  = NEW ZCL_GW_MODEL( ).
data table_name type c LENGTH 40 value 'KNA1'.

lo_mkna1->MAP_TO_TABLE(
  exporting
    TABLE     =  REF #( lr_mkna1 )
    TABLE_NAME = table_name
*    MODEL       = io_model
).

Al hacer debugg en la clase abstracta nunca entra en:

ASSIGN COMPONENT component->name OF STRUCTURE <table> TO <comp>.
sy-subrc siempre devuelve 4, con lo que no entra nunca para cargar los datos en:

DATA(method_name) = |GET_{ component->name }|.
CALL METHOD me->(method_name)
PARAMETER-TABLE parameters.

Alguien puede decirme que se me está escapando. ¿quizás estoy pasando mal los valores a MAP_TO_TABLE en el programa?

Muchas gracias