protected function encodeString($string)
    {
        if (is_null($string)) {
            return self::NULL;
        } else {
            return strtr($string, self::$encodeMap);
        }
    }
protected function encodeString($string)
    {
        if (is_null($string)) {
            return self::NULL;
        } else {
            return strtr($string, self::$encodeMap);
        }
    }
protected function encodeString ( $ string ) { if ( is_null ( $ string ) ) { return self :: NULL ; } else { return strtr ( $ string , self :: $ encodeMap ) ; } }
Encode string for sending to server

@param string $string

@return string
Encode string for sending to server