Method getDefaultCurrencyCode

/*
 * XML Feed only
 */
public static function getDefaultCurrencyCode()
{
    if (self::$defaultcurrencycode === false) {
        $db = Factory::getDBO();
        $query = ' SELECT a.code FROM #__phocacart_currencies AS a' . ' WHERE a.exchange_rate = 1' . ' ORDER BY a.code';
        $db->setQuery($query);
        $c = $db->loadObject();
        if (!empty($c->code)) {
            self::$defaultcurrencycode = $c->code;
        } else {
            self::$defaultcurrencycode = false;
        }
    }
    return self::$defaultcurrencycode;
}