I'm trying to understand the structure of a Cocoa document based application. I understand that the app delegate responds to events from the application (hence its name) and that the document controller manages all documents and open and save etc. What I'm not understanding is the connection between the document controller and the app delegate, and perhaps the rest of the application.
I'm studying this image, found here.
The arrow seems to indicate some kind of connection between the app delegate and the document controller.
What connection do they have?
Edit: I realize that this is a very academic question, that might no be so necessary, but I want to understand why these things are as they are.
