static function get_extrif_to_dc_transformer() { if (is_null(self::$extrif_to_dc_transformer)) { $extRifToDC = new DomDocument(); $extRifToDC->load(REGISTRY_APP_PATH . 'registry_object/transforms/extrif_to_dc.xsl'); $extRifToDCproc = new XSLTProcessor(); $extRifToDCproc->importStyleSheet($extRifToDC); self::$extrif_to_dc_transformer = $extRifToDCproc; } return self::$extrif_to_dc_transformer; }