public function getUri()
    {
        if ($this->valid() === false) {
            require_once 'Zend/Uri/Exception.php';
            throw new Zend_Uri_Exception('One or more parts of the URI are invalid');
        }

        $password = strlen($this->_password) > 0 ? ":$this->_password" : '';
        $auth     = strlen($this->_username) > 0 ? "$this->_username$password@" : '';
        $port     = strlen($this->_port) > 0 ? ":$this->_port" : '';
        $query    = strlen($this->_query) > 0 ? "?$this->_query" : '';
        $fragment = strlen($this->_fragment) > 0 ? "#$this->_fragment" : '';

        return $this->_scheme
             . '://'
             . $auth
             . $this->_host
             . $port
             . $this->_path
             . $query
             . $fragment;
    }