/**
  * @static
  * @return JoinControllerFactory
  */
 public static function getInstance()
 {
     if (!isset(self::$factory)) {
         self::$factory = new DefaultJoinControllerFactory();
     }
     return self::$factory;
 }
 protected function __construct() {
     parent::__construct();
     $this->handlerConfigurations = module_invoke_all('dp_join_method');
 }