Method getPreferredSku

public static function getPreferredSku()
{
    $app = Factory::getApplication();
    $paramsC = PhocacartUtils::getComponentParameters();
    $pos_preferred_sku = $paramsC->get('pos_preferred_sku', 'sku');
    $a = array();
    $a['name'] = $pos_preferred_sku;
    switch ($pos_preferred_sku) {
        case 'upc':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_UPC_LABEL');
            break;
        case 'ean':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_EAN_LABEL');
            break;
        case 'jan':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_JAN_LABEL');
            break;
        case 'isbn':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_ISBN_LABEL');
            break;
        case 'mpn':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_MPN_LABEL');
            break;
        case 'serial_number':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_SERIAL_NUMBER_LABEL');
            break;
        case 'registration_key':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_REGISTRATION_KEY_LABEL');
            break;
        default:
        case 'sku':
            $a['title'] = Text::_('COM_PHOCACART_FIELD_SKU_LABEL');
            break;
    }
    return $a;
}