About ABAP Object

Question

Hello All,
i have some question about ABAP Object.
What is the meaning of friend class and singleton?
Regards,
Luke

Answer 1

Hi,
The addition Friends makes class class a friend of classes classi and or interfaces ifaci.At the sam time, all subclasses of classes classi, all classes that implement one of the interfaces ifaci and all interfaces that have one of the interfaces ifaci as a component interface become friends of class. you have to specify at least one class or interface.
The friends of a class have unrestricted access to the protected and private components of that class, and can generate unrestricted instances of the class.
The friends of class are not automatically friends of subclasses of class. the addition Friends does not make class a friend of its friends.
Thea ddition global is allowed only when you use the addition public for the global class of a class pool at the same time.You can list other global classes and interfaces from the class library after global friends.This addition is generated when the Class Builder creates a global class and you specified friends at the corresponding tab page of the class Builder.
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In the example , classs c2 is a friend of interface i1, and therefore also of the implementing class c1. It can instantiate these objects and access their private component a1.
interface i1.
endinterface.
class c1 definition create private friends i1.
private section.
data a1(10) type c value 'Class 1'.
endclass.
class c2 definition.
public section.
interfaces i1.
methods m2.
endclass.
class c2 implementation.
method m2.
data oref type ref to c1.
create object oref.
write oref->a1.
endmethod.
enclass.
Kindly Reward Points If You Found The Reply Helpful,
Cheers,
Chaitanya.