@Override
    protected Optional<String> get(HttpRequest httpRequest, HttpResponse httpResponse, StopWatch stopWatch) throws Exception {

        try {
            return fromNullable(filter(new QueryStringDecoder(httpRequest.getUri()).getParameters().entrySet().stream()
                    .collect(toMap(
                            e -> {
                                if (e.getKey().length() > 1)
                                    throw new IllegalArgumentException("Multiple parameter values not supported");

                                if(parameters.contains(e.getValue().get(0).toLowerCase()))
                                    return Filters.valueOf(e.getKey());
                                else
                                    throw new IllegalArgumentException(format("Illegal parameter [key=%s]", e.getValue().get(0)));
                            },
                            e -> e.getValue().get(0)))).getContent());
        } catch (IllegalArgumentException e) {
            httpResponse.setStatus(HttpResponseStatus.BAD_REQUEST);
            return fromNullable(e.getMessage());
        } catch (Exception e) {
            httpResponse.setStatus(HttpResponseStatus.INTERNAL_SERVER_ERROR);
            return fromNullable(e.getMessage());
        }
    }