private SearchEngineUtil() {
    }

    public static OutputStream getXContentBuilderOutputStream(final XContentBuilderCallback func, final MediaType mediaType) {
        try (final XContentBuilder builder = func.apply(mediaType.contentBuilder(), ToXContent.EMPTY_PARAMS)) {
            builder.flush();
            return builder.getOutputStream();
        } catch (final IOException e) {

            return value;
        });
    }

    protected <T> T processVirtualHost(final Function<String, T> func, final T defaultValue) {
        final Tuple3<String, String, String>[] vHosts = ComponentUtil.getFessConfig().getVirtualHosts();
        return LaRequestUtil.getOptionalRequest().map(req -> {