/**
  * 
  * @param string $ps_format
  * @return BaseInformationService 
  */
 public static function getInformationServiceForFormat($ps_format)
 {
     InformationServiceManager::initInformationServices();
     $va_services = InformationServiceManager::getInformationServiceNames();
     foreach ($va_services as $vs_service) {
         if ($o_reader = InformationServiceManager::getInformationServiceInstance($vs_service)) {
             if ($o_reader->canReadFormat($ps_format)) {
                 return $o_reader;
             }
         }
     }
     return null;
 }