code: @Override
      public int compareTo(Role role) {
          if (!role.getServer().equals(getServer())) {
              throw new IllegalArgumentException("Only roles from the same server can be compared for order");
          }
          return ROLE_COMPARATOR.compare(this, role);
      }
docs: {@inheritDoc}
  
  <p><b><i>Implementation note:</i></b> Only roles from the same server can be compared
  
  @throws IllegalArgumentException If the roles are on different servers.