final FessConfig fessConfig = ComponentUtil.getFessConfig();

        try {
            if (!fessConfig.validateIndexRequiredFields(doc)) {
                throwError.accept(messages -> fessConfig.invalidIndexRequiredFields(doc)
                        .stream()
                        .map(s -> "doc." + s)
                        .forEach(s -> messages.addErrorsPropertyRequired(s, s)));
            }