Creating a Factory in ABAP.

Question

HI ,
I have a requirement to implement the Factory pattern for my class.
I have declared my class as private so that direct instantiation is avoided.
A factory class has been created to instantiate my class , but i cannot instantiate my class since my class is declared as a private class.
Would it be a good option to declare the Factory class as a FRIEND in my class. This would destroy the encapsulation of my private attributes , but the factory would not have any other functionality apart from instance creation.
Kindly provide some suggestions.
Regards,
Newton.

Answer 1

It wont be possible to instantiate a different class with the same factory method.
I am not sure where you heading to. Are you going to use the same factory method/class to instantiate different class objects? If so this would require some generic factory class which could be only used if it was a FRIEND class of the instantiated one (this already you noticed). This would work similary to peristent objects concept, where agent class inherits from base class which in turn has FRIENDS relationship with persisent class . This way agent can instantiate persistent . Using inheritance as suggested by dsp would ban to use any other parental class. Interface, on the other hand would require implementation for every single class using it. So the choice is up to you, depending how generic you want the factory be.
Regards
Marcin