Understanding Instance and Static Components

Steps

• Go to transaction code SE24.

• The initial screen of Class Builder looks like this.

•  Enter the Object Type (class name ), start's with YCL_ or ZCL_ <class name >, and click on create button.

• Enter the short description and click on the SAVE button.

• Save it in either Package or Local Package.

• Class Interface looks like this.

• Click on the attributes Tab,

• Enter the attribute name.

• Click on Level and press F4 help.

• Select the Level  ( instance ) of the attribute.

• Click on Visibility and press F4 help.

• Select the Visibility of the attribute.

• Enter the Associated type( data type ).

• Enter the Description.

• Enter the initial value ( optional ).

• Note: N1 is known as the Instance Public attribute.
• To Add a static public attribute follow the following steps.
• Enter attribute name.

• Click on Level and press F4 help.

• Select static attribute.

• Click on Visibility and press F4 help.

• Select the visibility.

 

•  Enter the Associated Type.

•  Enter the description.

• Enter the initial value.

• Similarly, create different attributes as shown below as per Level and Visibility.

• Note :

1. N3 is known as instance protected.
2. N4 is known as static protected.
3. N5 is known as instance private.
4. N6 is known as static private.

• Save -> Check -> Activate.

Understanding Instance and Static Components

• Go to transaction code SE38.

• Enter the program name start's with Y or Z<program name > and click on create button.

• Enter the Title, select attribute type as an executable program, and click on Save.

• To declare the object.

                     DATA : <object name > Type  <Class name >.

• Ex : obj type ZCL_FIRST_CLASS.

• To create the object.

                 CREATE OBJECT < object name> .

• Ex: Create object OBJ.

• We can call instance attributes using ,

            <object name >-><attribute name>.

• We can call static attribute using,

                  <object name >-><attribute name>.

                          

                               or

                  <Class name >=><attribute name>.

• Call attributes default values.

• Save -> Check->Activate.
• Execute.

• Change the values of instance and static public attributes.

• Save ->Check->Attributes.
• Execute.

• Now call another object attributes.

• Save -> Check -> Activate.

Note: Whenever a static attribute changes its value, then the static attribute changes its initial value.

Source Code.

DATA : OBJ TYPE REF TO ZCL_FIRST_CLASS,
       OBJ2 TYPE REF TO ZCL_FIRST_CLASS.

START-OF-SELECTION.

CREATE OBJECT: OBJ , OBJ2.

"Call attributes default values

WRITE : / ' N1 INSTANCE PUBLIC ATTRIBUTE : ' , OBJ->N1.
WRITE : / ' N2 INSTANCE PUBLIC ATTRIBUTE : ' , OBJ->N2.

ULINE.

" CHANGE THE VALUES OF  INSTANCE AND STATIC PUBLIC ATTRIBUTE VALUE

OBJ->N1 = 76.
OBJ->N2 = 34.

WRITE : / ' N1 INSTANCE PUBLIC ATTRIBUTE : ' , OBJ->N1.
WRITE : / ' N2 INSTANCE PUBLIC ATTRIBUTE : ' , OBJ->N2.

" Now call the object 2.
uline .

WRITE : / ' N1 INSTANCE PUBLIC ATTRIBUTE : ' , OBJ2->N1.
WRITE : / ' N2 INSTANCE PUBLIC ATTRIBUTE : ' , OBJ2->N2.

ULINE.