public boolean isReadOnly(Resource resource)
  {
    if (resourceToReadOnlyMap == null)
    {
      return false;
    }
    else
    {
      Boolean result = resourceToReadOnlyMap.get(resource);
      if (result == null && resource != null)
      {
        Map<?, ?> options = Collections.singletonMap(URIConverter.OPTION_REQUESTED_ATTRIBUTES, Collections.singleton(URIConverter.ATTRIBUTE_READ_ONLY));
		Map<String, ?> attributes = (resource.getResourceSet() == null ? resourceSet : resource.getResourceSet()).getURIConverter().getAttributes(resource.getURI(), options);
        result = Boolean.TRUE.equals(attributes.get(URIConverter.ATTRIBUTE_READ_ONLY));
        resourceToReadOnlyMap.put(resource, result);
      }
      return Boolean.TRUE.equals(result);
    }
  }