title: How to define an action as separated class in SF2?
body: <p>I have been worked with YF some time and I know that in YF is a beautiful thing - an ability to define an action as separated class. Look <a href="http://www.yiiframework.com/doc/guide/1.1/en/basics.controller" rel="nofollow">this page</a> (paragraph - 3. Action) for details.</p>
  
  <p>I wonder, is it possible to do it in SF2?</p>
  
  <p>For SF I found the following solution: extending a class sfAction. What about SF2?</p>