private void computeMeanRatings(int userId) {
        List<UserRatingsList> userRatings = ratingsTable.getRatingsTable();
        Map<Integer, BigDecimal> targetUserRatingsTable = ratingsTable.getRatingsByUserId(userId).getRatingsMap();
        for (int i = 0; i < userRatings.size(); i++) {
            Map<Integer, BigDecimal> userRatingsTable = userRatings.get(i).getRatingsMap();
            BigDecimal meanRating = new BigDecimal(0.0);
            int count = 0;
            List<Integer> intersectingIds = new ArrayList<Integer>();
            for (Integer movieIndex : userRatingsTable.keySet()) {
                    count++;
                    intersectingIds.add(movieIndex);
                    meanRating = meanRating.add(userRatingsTable.get(movieIndex), new MathContext(6));
            }
            meanRating = meanRating.divide(new BigDecimal(count), new MathContext(6));
            meanRatings.put(i, meanRating);
        }

    }