Beispiel zur objektorientierten Programmierung

*&---------------------------------------------------------------------*
*& Report  ZZ_##_OBJECTS
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*
 
REPORT  zz_##_objects.
 
*----------------------------------------------------------------------*
*       CLASS counter DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter DEFINITION.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING init_value TYPE i,
             increment,
             write,
             whoami.
  PROTECTED SECTION.
    DATA value TYPE i.
ENDCLASS.                    "counter DEFINITION
 
*----------------------------------------------------------------------*
*       CLASS counter IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter IMPLEMENTATION.
  METHOD constructor.
    value = init_value.
  ENDMETHOD.                    "constructor
  METHOD increment.
    ADD 1 TO value.
  ENDMETHOD.                    "increment
  METHOD write.
    WRITE / value.
  ENDMETHOD.                    "write
  METHOD whoami.
    WRITE /'Ich bin der Basiszähler'.
  ENDMETHOD.                    "whoami
ENDCLASS.                    "counter IMPLEMENTATION
 
*----------------------------------------------------------------------*
*       CLASS counter_10 DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter_10 DEFINITION INHERITING FROM counter.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING init_value TYPE i,
             increment REDEFINITION,
             write REDEFINITION,
             whoami REDEFINITION.
    DATA value_10 TYPE i.
ENDCLASS.                    "counter_10 DEFINITION
 
*----------------------------------------------------------------------*
*       CLASS counter_10 IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter_10 IMPLEMENTATION.
  METHOD constructor.
    CALL METHOD super->constructor
      EXPORTING
        init_value = init_value.
    value_10 = value DIV 10.
  ENDMETHOD.                    "constructor
  METHOD increment.
    CALL METHOD super->increment.
    value_10 = value DIV 10.
  ENDMETHOD.                    "increment
  METHOD write.
    CALL METHOD super->write.
    WRITE value_10.
  ENDMETHOD.                    "write
  METHOD whoami.
    WRITE /'Ich bin der Zehnerzähler'.
  ENDMETHOD.                    "whoami
ENDCLASS.                    "counter_10 IMPLEMENTATION
 
*----------------------------------------------------------------------*
*       CLASS counter_20 DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter_20 DEFINITION INHERITING FROM counter.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING init_value TYPE i,
             increment REDEFINITION,
             write REDEFINITION,
             whoami REDEFINITION.
    DATA value_20 TYPE i.
ENDCLASS.                    "counter_20 DEFINITION
 
*----------------------------------------------------------------------*
*       CLASS counter_20 IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter_20 IMPLEMENTATION.
  METHOD constructor.
    CALL METHOD super->constructor
      EXPORTING
        init_value = init_value.
    value_20 = value DIV 20.
  ENDMETHOD.                    "constructor
  METHOD increment.
    CALL METHOD super->increment.
    value_20 = value DIV 20.
  ENDMETHOD.                    "increment
  METHOD write.
    CALL METHOD super->write.
    WRITE value_20.
  ENDMETHOD.                    "write
  METHOD whoami.
    WRITE /'Ich bin der Zwanzigerzähler'.
  ENDMETHOD.                    "whoami
ENDCLASS.                    "counter_20 IMPLEMENTATION
 
DATA: count TYPE REF TO counter,
      number TYPE i VALUE 0.
 
DATA: a TYPE REF TO counter,
      b TYPE REF TO counter,
      c TYPE REF TO counter,
      x TYPE REF TO counter,
      y TYPE REF TO counter,
      z TYPE REF TO counter.
 
START-OF-SELECTION.
 
  CREATE OBJECT count
    EXPORTING
      init_value = number.
 
  DO 42 TIMES.
    CALL METHOD count->increment.
    CALL METHOD count->write.
  ENDDO.
 
  ULINE.
 
  CREATE OBJECT count
    TYPE
      counter_10
    EXPORTING
      init_value = number.
 
  DO 42 TIMES.
    CALL METHOD count->increment.
    CALL METHOD count->write.
  ENDDO.
 
  ULINE.
 
  CREATE OBJECT count
    TYPE
      counter_20
    EXPORTING
      init_value = number.
 
  DO 42 TIMES.
    CALL METHOD count->increment.
    CALL METHOD count->write.
  ENDDO.
 
  ULINE.
 
  CREATE OBJECT a
    EXPORTING
      init_value = number.
 
  CREATE OBJECT b
    TYPE
      counter_10
    EXPORTING
      init_value = number.
 
  CREATE OBJECT c
    TYPE
      counter_20
    EXPORTING
      init_value = number.
 
  CREATE OBJECT x
    EXPORTING
      init_value = number.
 
  CREATE OBJECT y
    TYPE
      counter_10
    EXPORTING
      init_value = number.
 
  CREATE OBJECT z
    TYPE
      counter_20
    EXPORTING
      init_value = number.
 
  CALL METHOD a->whoami.
  CALL METHOD b->whoami.
  CALL METHOD c->whoami.
  CALL METHOD x->whoami.
  CALL METHOD y->whoami.
  CALL METHOD z->whoami.