ABAP objects design patterns

Question

hi all,
    can any one send me the Design patterns used for ABAP objects programming in ABAP. eg mvc and sample code which uses the design patterns
cheers
senthil

Answer 1

Of course that program is not an object design pattern
(Its just a little ABAP Objects syntax demo that I wrote  years ago
I don't know about a list of OO design patterns implemented in ABAP Objects.
A very simple one, a Singleton might look like this:
<b>* cl_singleton: Eager Variant
CLASS cl_singleton DEFINITION FINAL
                              CREATE PRIVATE.
  PUBLIC SECTION.
    CLASS-METHODS: class_constructor,
                   get_singleton RETURNING VALUE(singleton)
                                           TYPE REF TO cl_singleton.
  PRIVATE SECTION.
    CLASS-DATA singleton TYPE REF TO cl_singleton.
ENDCLASS.
CLASS cl_singleton IMPLEMENTATION.
  METHOD class_constructor.
    CREATE OBJECT singleton.
  ENDMETHOD.
  METHOD get_singleton.
    singleton = cl_singleton=>singleton.
  ENDMETHOD.
ENDCLASS.
cl_singleton: Lazy Variant
CLASS cl_singleton DEFINITION FINAL
                              CREATE PRIVATE.
  PUBLIC SECTION.
    CLASS-METHODS get_singleton RETURNING VALUE(singleton)
                                          TYPE REF TO cl_singleton.
  PRIVATE SECTION.
    CLASS-DATA singleton TYPE REF TO cl_singleton.
ENDCLASS.
CLASS cl_singleton IMPLEMENTATION.
  METHOD get_singleton.
    IF cl_singleton=>singleton IS INITIAL.
      CREATE OBJECT cl_singleton=>singleton.
    ENDIF.
    singleton = cl_singleton=>singleton.
  ENDMETHOD.
ENDCLASS.</b>