public ConfigLoader getServerConfig() {
   if (useServerConfig && serverConfig == null) {
     // TODO Use mapModel instead of parsing RDF again
     serverConfig =
         new ConfigLoader(mappingFile == null ? null : ConfigLoader.toAbsoluteURI(mappingFile));
     serverConfig.load();
   }
   return serverConfig;
 }
 /** @return Base URI where the server is assumed to run */
 public String getSystemBaseURI() {
   if (baseURI != null) {
     return D2RQReader.absolutizeURI(baseURI);
   }
   if (getServerConfig() != null && serverConfig.baseURI() != null) {
     return serverConfig.baseURI();
   }
   if (getPort() == 80) {
     return DEFAULT_PROTOCOL + "://" + DEFAULT_HOST + "/";
   }
   return DEFAULT_PROTOCOL + "://" + DEFAULT_HOST + ":" + getPort() + "/";
 }