php - How to use defined data as function or class name? -

I have defined a data as below.

  Define ('INDEX_CONTROLLER', 'test');   
 and I want to use it as below.  
  need_once 'Controller /' INDEX_CONTROLLER '.php'; $ This- & gt; Admin = new INDEX_CONTROLLER ();   
 I'm getting the error below.  
 
 Fatal error: Class 'INDEX_CONTROLLER' /var/www/own/boot.php not found in you You can set it to a variable and then call it:    
 
 < Previous>  $ controller = INDEX_CONTROLLER; $ This- & gt; Controller = new $ controller ();