protected function convertRelationType($stringType)
    {
        $stringTypeList = explode(',', strtoupper($stringType));
        $relationType = 0;

        foreach ($stringTypeList as $stringTypeValue) {
            switch ($stringTypeValue) {
                case 'COMMON':
                    $relationType |= Values\Content\Relation::COMMON;
                    break;
                case 'EMBED':
                    $relationType |= Values\Content\Relation::EMBED;
                    break;
                case 'LINK':
                    $relationType |= Values\Content\Relation::LINK;
                    break;
                case 'FIELD':
                    $relationType |= Values\Content\Relation::FIELD;
                    break;
                case 'ASSET':
                    $relationType |= Values\Content\Relation::ASSET;
                    break;
                default:
                    throw new \RuntimeException(
                        sprintf('Unknown Relation type: "%s"', $stringTypeValue)
                    );
            }
        }

        return $relationType;
    }