In "cache" class, where does directory setup go?

Question

I have a class that is used to store and retrieve image data from a cache using NSFileManager. When an instance of it is created, I want to check whether the image directory already exists, and if not, create it. Where is the most appropriate place to put this code? Is this something one would override the designated initializer for?

Thanks for reading.

Answer 1

The initialiser (init) function would be the best place to do it from a programming perspective because the rest of the instance methods would probably rely on having access to the directory to store/retrieve images.

You'd also want any instances created to know whether the accessing/creating was successful so in your initialiser you may wish to put some error handling which returns a nil instance (or throws an exception) if it can't be accessed which can then be handled by the classes which use the instance of your cache class.