private function validUsername($username)
 {
     if (strlen($username) < $this->minUserLength) {
         $this->errorArray[] = "Användarnamnet är för kort, minst " . $this->minUserLength . " tecken";
         return false;
     }
     $registerDAL = new RegisterDAL();
     if (!$registerDAL->isUserNameFree($username)) {
         $this->errorArray[] = $this->userTaken;
         return false;
     }
     if (preg_match('/^[<a-zA-Z0-9]*$/', $username)) {
         return true;
     } else {
         $this->errorArray[] = $this->userNameError;
         return false;
     }
 }