ABAP面向对象之EVENT处理

CLASS counter DEFINITION.

  PUBLIC SECTION.

    METHODS increment_counter.

    EVENTS  critical_value EXPORTING value(excess) TYPE i.

  PRIVATE SECTION.

    DATA: count     TYPE i,

          threshold TYPE i VALUE 10.

ENDCLASS.

CLASS counter IMPLEMENTATION.

  METHOD increment_counter.

    DATA diff TYPE i.

    ADD 1 TO count.

    IF count > threshold.

      diff = count - threshold.

      RAISE EVENT critical_value EXPORTING excess = diff.

    ENDIF.

  ENDMETHOD.

ENDCLASS.

CLASS handler DEFINITION.

  PUBLIC SECTION.

    METHODS handle_excess FOR EVENT critical_value OF counter

            IMPORTING excess.

ENDCLASS.

CLASS handler IMPLEMENTATION.

  METHOD handle_excess.

    WRITE: / 'Excess is', excess.

  ENDMETHOD.

ENDCLASS.

DATA: r1 TYPE REF TO counter,

      h1 TYPE REF TO handler.

START-OF-SELECTION.

  CREATE OBJECT: r1, h1.

  SET HANDLER h1->handle_excess FOR ALL INSTANCES.

  DO 20 TIMES.

    CALL METHOD r1->increment_counter.

  ENDDO.