protected function loadMetadata(bool $force = false) {
        if (!$this->metadata || $force) {
            $meta = $this->getMetadataFromFedora();

            if (count($meta->propertyUris()) === 0) {
                throw new RuntimeException('No resource metadata. Please check a value of the fedoraApiUrl configuration property.');
            }

            $this->setMetadata($meta);
        }
    }