/**
* Returns an singleton instance of this class
* @return
*/
public static function getInstance()
{
if (self::$instance == null) {
self::$instance = new DeviceCounterHistoryMapper();
}
return self::$instance;
}
/**
* Initializes DB mappers
*
* @return
*/
function __construct()
{
$this->mapper = DeviceCounterHistoryMapper::getInstance();
}