*ABAP Objects - Creating your First Local Class* *Author: Marcelo Ramos*  Class One Definition  *----------------------------------------------------------------------* *       CLASS ONE DEFINITION *----------------------------------------------------------------------* CLASS one DEFINITION.    PUBLIC SECTION. *   The constructor method must be definited on Public Section *   Here we're definig a constructor method without parameters.     METHODS constructor.      METHODS get_attribute RETURNING value(value) TYPE char10.    PRIVATE SECTION.      DATA attribute TYPE char10.  ENDCLASS.                    "ONE DEFINITION  Class One Implementation  *----------------------------------------------------------------------* *       CLASS one IMPLEMENTATION *----------------------------------------------------------------------* CLASS one IMPLEMENTATION.    METHOD constructor. *   Inside Construcot we can initialize attributes, call othres methods, etc...     MOVE 'value X' TO attribute.    ENDMETHOD.                    "CONSTRUCTOR    METHOD get_attribute.      MOVE attribute TO value.    ENDMETHOD.                    "get_attribute ENDCLASS.                    "one IMPLEMENTATION  Class Two Definition  *----------------------------------------------------------------------* *       CLASS two DEFINITION *----------------------------------------------------------------------* CLASS two DEFINITION.    PUBLIC SECTION.  *   Here we're definig a constructor method with a parameter. *   Constructor can have only import parameters and its can be defineted *   as Optional     METHODS constructor IMPORTING value TYPE char10 OPTIONAL.      METHODS get_attribute RETURNING value(value) TYPE char10.    PRIVATE SECTION.      DATA attribute TYPE char10.  ENDCLASS.                    "two DEFINITION  Class Two Implementation  *----------------------------------------------------------------------* *       CLASS two IMPLEMENTATION *----------------------------------------------------------------------* CLASS two IMPLEMENTATION.    METHOD constructor.      IF value IS NOT INITIAL.       MOVE value TO attribute.     ELSE.       MOVE 'Value Y' TO attribute.     ENDIF.   ENDMETHOD.                    "CONSTRUCTOR    METHOD get_attribute.      MOVE attribute TO value.    ENDMETHOD.                    "get_attribute  ENDCLASS.                    "two IMPLEMENTATION  Creation Object  DATA o_one TYPE REF TO one. DATA o_two TYPE REF TO two. DATA o_two2 TYPE REF TO two.  DATA atribute TYPE char10.  Instance Creation  START-OF-SELECTION.  * As Constructor of class one doesn't has parameters we can create its object as follow   CREATE OBJECT o_one.    atribute = o_one->get_attribute( ).   WRITE / atribute.   CLEAR atribute.  * As parameter was definited as Optional we can pass the parameter during object instantiation.   CREATE OBJECT o_two     EXPORTING       value = 'Value Z'.    atribute = o_two->get_attribute( ).   WRITE / atribute.   CLEAR atribute.  * Or we can just pass a null value Like value = ' '. or value = SPACE.   CREATE OBJECT o_two     EXPORTING       value = ' '.    atribute = o_two->get_attribute( ).   WRITE / atribute.   CLEAR atribute.  * As parameter was definited as Optional we can miss the parameter during object instantiation.   CREATE OBJECT o_two2.    atribute = o_two2->get_attribute( ).   WRITE / atribute.   CLEAR atribute.  The atribute value is printed  value X Value Z Value Y Value Y