topic Re: Class concept in Application Development and Automation Discussions

Class concept

Former Member — Wed, 05 Mar 2008 13:59:46 GMT

when we use double arrow symbol (==>) and when we use single arrow symbol in OOPS concepts..

Re: Class concept

Former Member — Wed, 05 Mar 2008 14:11:51 GMT

=> this is used for static methods and static attributes.

-> used for Instance methods and Instance attribute.

Instance components exist separately in each instance (object) of the class and are referred using instance component selector using '->'

.Static components only exist once per class and are valid for all instances of the class. They are declared with the CLASS- keywords

Static components can be used without even creating an instance of the class and are referred to using static component selector ‘ =>’ .

See the below example u can better understand the concept:

REPORT YSUBOOPS17 .

CLASS c1 DEFINITION.

PUBLIC SECTION.

data : i_num type i value 5.

class-data :

s_num type i value 6 .

ENDCLASS.

CLASS c1 IMPLEMENTATION.

ENDCLASS.

START-OF-SELECTION.

DATA : oref1 TYPE REF TO c1 .

CREATE OBJECT : oref1.

write:/5 oref1->i_num.

write:/5 c1=>s_num .

write:/5 oref1->s_num.

<REMOVED BY MODERATOR>

Regards

Pratap.M

Edited by: Alvaro Tejada Galindo on Mar 5, 2008 6:13 PM

Re: Class concept

Former Member — Thu, 06 Mar 2008 04:17:24 GMT

-> Object Component Selector

To access instance components from outside the class using obj->comp.

ME->comp can be used to point to the instance components and static components of this class.

=> Class Component Selector

You can access the static components from outside the class with the expression class=>comp

Static Access

The following syntax applies (ref is a reference variable):

Access to an instance attribute attr: ref->attr

Calling an instance method meth: CALL METHOD ref->meth

In addition to reference variables, the class name can be used for access:

Accessing a static attribute attr: class=>attr

Calling a static method meth: CALL METHOD class=>meth

Dynamic Access

The following syntax applies (ref is a reference variable):

Calling an instance method meth: CALL METHOD ref->(f)

Calling a static method meth: CALL METHOD class=>(f) CALL METHOD (c)=>meth CALL METHOD (c)=>(f)

Calling own method meth: CALL METHOD (f) CALL METHOD ME->(f)