public static EndpointReferenceFactory getInstance(QName endpointRefName, String refScheme) {
   for (int i = 0, n = factories.size(); i < n; i++) {
     EndpointReferenceFactory factory = (EndpointReferenceFactory) factories.get(i);
     if (factory.acceptsReference(endpointRefName, refScheme)) {
       return factory;
     }
   }
   return null;
 }
 public static void registerInstance(EndpointReferenceFactory instance) {
   factories.add(instance);
   log.debug("registered endpoint factory: " + instance.getClass().getName());
 }