title: Best place to check if a user is blocked by another
body: <p>If I want to introduce the concept of blocked users, where is the most appropriate place to make the check if a user is blocked, without breaking the principles of good design?</p>
  
  <p>Till now, I've been using Spring Security, to annotate the controller methods on whether a particular user has the permissions to do a certain action. With this blocked users thing, it gets a bit more complicated. Should I try to fit this again in the controller (possibly with Spring security again) or this is something which I should let the domain object decide itself?</p>
  
  <p>I guess it'd be better to leave this on the controller leve, but I fear if my controllers won't turn into an if...else mess one day.</p>