/**
  * Returns an instance of class (singleton pattern implementation).
  *
  * @return BOL_MediaPanelFileDao
  */
 public static function getInstance()
 {
     if (self::$classInstance === null) {
         self::$classInstance = new self();
     }
     return self::$classInstance;
 }
 /**
  * Constructor.
  *
  */
 protected function __construct()
 {
     $this->dao = BOL_MediaPanelFileDao::getInstance();
 }