code: @Override
      public com.ibm.websphere.security.UserRegistry getExternalUserRegistry(UserRegistry userRegistry) {
          if (userRegistry instanceof ExternalUserRegistryWrapper) {
              return ((ExternalUserRegistryWrapper) userRegistry).getExternalUserRegistry();
          }
          return new UserRegistryWrapper(userRegistry);
      }
docs: /*
  (non-Javadoc)
  
  @see com.ibm.ws.security.registry.UserRegistryService#getExternalUserRegistry(com.ibm.ws.security.registry.UserRegistry)