title: Java actionlistener actionPerformed in different class
body: <p>I have two classes: the main one and one called "Window".
  There are some buttons in the Window class, is it possible to let the "main" class know what happened? In short, buttons in class "Window" should trigger some stuff in the main class.</p>
  
  <p>Or should I just type everything in the "Window" class?</p>