ABAP面向对象之实现接口

INTERFACE status.
  METHODS write.
ENDINTERFACE.

CLASS counter DEFINITION.
  PUBLIC SECTION.
    INTERFACES status.
    METHODS increment.
  PRIVATE SECTION.
    DATA count TYPE i.
ENDCLASS.

CLASS counter IMPLEMENTATION.
  METHOD status~write.
    WRITE: / 'Count in counter is', count.
  ENDMETHOD.
  METHOD increment.
    ADD 1 TO count.
  ENDMETHOD.
ENDCLASS.

CLASS bicycle DEFINITION.
  PUBLIC SECTION.
    INTERFACES status.
    METHODS drive.
  PRIVATE SECTION.
    DATA speed TYPE i.
ENDCLASS.

CLASS bicycle IMPLEMENTATION.
  METHOD status~write.
    WRITE: / 'Speed of bicycle is', speed.
  ENDMETHOD.
  METHOD drive.
    ADD 10 TO speed.
  ENDMETHOD.
ENDCLASS.

DATA: count  TYPE REF TO counter,
      bike   TYPE REF TO bicycle,
      status TYPE REF TO status,
      status_tab TYPE TABLE OF REF TO status.

START-OF-SELECTION.

  CREATE OBJECT: count, bike.

  DO 5 TIMES.
    CALL METHOD: count->increment,
                 bike->drive.
  ENDDO.

  APPEND: count TO status_tab,
          bike  TO status_tab.

  LOOP AT status_tab INTO status.
    CALL METHOD status->write.
  ENDLOOP.