@Nullable
    @WorkerThread
    public static GCVoteRating getRating(final String guid, final String geocode) {
        if (StringUtils.isNotBlank(guid) && RATINGS_CACHE.containsKey(guid)) {
            return RATINGS_CACHE.get(guid);
        }

        final Map<String, GCVoteRating> ratings = getRating(singletonOrNull(guid), singletonOrNull(geocode));
        return MapUtils.isNotEmpty(ratings) ? ratings.values().iterator().next() : null;
    }
Get user rating for a given guid or geocode. For a guid first the ratings cache is checked
before a request to gcvote.com is made.
main/src/main/java/cgeo/geocaching/gcvote/GCVote.java