class UiExtension {

    public List<UiView> views() {
        return isValid ? views : ImmutableList.of();
    }

    private  UiExtension(ClassLoader cl, String path, List<UiView> views,
                        UiMessageHandlerFactory mhFactory,
                        UiTopoOverlayFactory toFactory,
                        UiTopoMapFactory tmFactory);

}