ABAP Real time object for To Use BADI - Business Add In you need to Understand ABAP OO Interface Concept

Report Z_CTRY.

* A Shape Interface "Like a shape" "Behaves like a Shape"
Adverb/Adjective

Interface IShape.
Methods:  getArea Returning Value(area) Type F,
         getCircumference Returning Value(circumference) Type F.
Endinterface.

* A Circle Class that behaves like a Shape
Class CCircle Definition.

   Public Section.

       Interfaces IShape.

       Aliases:   getArea For IShape~getArea,
                  getCircumference For IShape~getCircumference.

       Methods:   Constructor Importing pRadius Type F,
                  setRadius   Importing pRadius Type F,
                  getRadius   Returning Value(pRadius) Type F.

   Private Section.
       Data radius Type F.
       Constants PI Type F Value '3.141592365359'.
EndClass.

Class CCircle Implementation.

   Method Constructor.
       radius = pRadius.
   EndMethod.

   Method setRadius.
       radius = pRadius.
   EndMethod.

   Method getRadius.
       pRadius = radius.
   EndMethod.

   Method IShape~getArea.
       Compute area = 2 * PI * radius.
   EndMethod.

   Method IShape~getCircumference.
       Compute circumference = PI * radius * radius.
   EndMethod.

EndClass.

* A Square Class
Class CSquare Definition.

   Public Section.

       Interfaces IShape.

       Aliases:   getArea For IShape~getArea,
                  getCircumference For IShape~getCircumference.

       Methods:   Constructor Importing pSide Type F.

   Private Section.
       Data side Type F.
EndClass.

Class CSquare Implementation.

   Method Constructor.
       side = pSide.
   EndMethod.

   Method IShape~getArea.
       Compute area = side * side.
   EndMethod.

   Method IShape~getCircumference.
       Compute circumference = 4 * side.
   EndMethod.

EndClass.

* A Rectangle Class
Class CRectangle Definition.

   Public Section.

       Interfaces IShape.

       Aliases:   getArea For IShape~getArea,
                  getCircumference For IShape~getCircumference.

       Methods:   Constructor Importing pHeight Type F
                                        pLength Type F.

   Private Section.
       Data: height Type F,
             length Type F.
EndClass.

Class CRectangle Implementation.

   Method Constructor.
       height = pHeight.
       length = pLength.
   EndMethod.

   Method IShape~getArea.
       Compute area = height * length.
   EndMethod.

   Method IShape~getCircumference.
       Compute circumference = 2 * ( height + length ).
   EndMethod.

EndClass.

* START of PROGRAM

* Array of Shapes
Data:  OneShape   Type Ref To IShape,             " One Object with
Shape Behaviour
      ShapeTable Type Table Of Ref To IShape.    " Array of Objects
with Shape Behaviour

* Concrete Objects with IShape Behaviour!
Data:  C1 Type Ref To CCircle,
      S1 Type Ref To CSquare,
      R1 Type Ref To CRectangle,
      C2 Type Ref To CCircle,
      S2 Type Ref To CSquare,
      R2 Type Ref To CRectangle.


Data:  descr_ref  TYPE ref to CL_ABAP_TYPEDESCR,
      ClassName  Type String,
      Serial     Type I.

Data:  myArea          Type F,
      myCircumference Type F.

START-OF-SELECTION.
   Create Object C1 Exporting pRadius = '2.5'.
   Create Object C2 Exporting pRadius = '5.0'.

   Create Object S1 Exporting pSide = '3.5'.
   Create Object S2 Exporting pSide = '6.0'.

   Create Object R1 Exporting pHeight = '2.8' pLength = '3.4'.
   Create Object R2 Exporting pHeight = '1.7' pLength = '6.3'.

* Append in any order!
   Append S1  to ShapeTable.
   Append R2  to ShapeTable.
   Append R1  to ShapeTable.
   Append C2  to ShapeTable.
   Append C1  to ShapeTable.
   Append S2  to ShapeTable.

   Serial = 0.

   Loop At ShapeTable into OneShape.
      Call Method OneShape->getArea
                            Receiving area = myArea.
      Call Method OneShape->getCircumference
                            Receiving circumference = myCircumference.

      descr_ref = CL_ABAP_TYPEDESCR=>Describe_By_Object_Ref( OneShape
).
      Call Method descr_ref->get_relative_name
                  Receiving P_RELATIVE_NAME = ClassName.

      Add 1 to Serial.

      Write: / Serial,  ClassName.
      Write: / 'Area          ',  myArea          Decimals 4 Exponent
0.
      Write: / 'Circumference ',  myCircumference Decimals 4 Exponent
0.
      Write: /.

   EndLoop.

** Results  
*           1  CSQUARE                      
*  Area                            12.2500  
*  Circumference                   14.0000  
*                                           
*           2  CRECTANGLE                   
*  Area                            10.7100  
*  Circumference                   16.0000  
*                                           
*           3  CRECTANGLE                   
*  Area                             9.5200  
*  Circumference                   12.4000  
*                                           
*           4  CCIRCLE                      
*  Area                            31.4159  
*  Circumference                   78.5398  
*                                           
*           5  CCIRCLE                      
*  Area                            15.7080  
*  Circumference                   19.6350  
*                                           
*           6  CSQUARE                      
*  Area                            36.0000  
*  Circumference                   24.0000