NatLibFi / Skosmos

     * @param string $lang

     * @return array array of labels (key: lang, val: label), or null if resource doesn't exist

     */

    public function queryLabel($uri, $lang) {

        $query = $this->generateLabelQuery($uri, $lang);

        $result = $this->query($query);

        $ret = array();

        foreach ($result as $row) {

            if (!isset($row->label)) {

                // existing concept but no labels

                return array();

            }

            $ret[$row->label->getLang()] = $row->label;

        }

        if (sizeof($ret) > 0) {

            // existing concept, with label(s)

            return $ret;

        } else {

            // nonexistent concept

            return null;

        }

    }

    /**

     * Generates a SPARQL query to retrieve the super properties of a given property URI.

     * @param string $uri URI of a propertyes

     * @return array array super properties, or null if none exist

     */

    public function querySuperProperties($uri) {

        $query = $this->generateSubPropertyOfQuery($uri);

        $result = $this->query($query);

        $ret = array();

        foreach ($result as $row) {

            if (isset($row->superProperty)) {

                $ret[] = $row->superProperty->getUri();

            }

        }

        if (sizeof($ret) > 0) {

            // return result

            return $ret;

        } else {

            // no result, return null

            return null;

        }

    }

    /**