public function setRoute($route)
        {
            if (null !== $route && (!is_string($route) || strlen($route) < 1)) {
                throw new Exception(
                    'Invalid argument: $route must be a non-empty string or null'
                );
            }

            $this->_route     = $route;
            $this->_hrefCache = null;

            return $this;
        }