When are observers observable? When you want them to be.
I'm always trying to make the patterns I use more functional without buying into functionality I might not need in some cases, and a good example is the Repository pattern
TLDR: I don't give a shit about whether I upset or offend anyone, this is my opinion from my experience of people in the PHP community, and I can be
Java has private classes that can reside inside other classes, and for a business domain model, this is a neat thing to be able to do in order to hide