// As this is used for testing - it is package private
  void addValue(Object xValue, Object yValue, int i) {
    Map yValues = (Map) xAxis.get(xValue);
    if (yValues == null) {
      yValues = new TreeMap(ComparatorSelector.getComparator(yAxisMapper));
      xAxis.put(xValue, yValues);
    }

    Number existingValue = (Number) yValues.get(yValue);
    yValues.put(yValue, statisticGatherer.getValue(existingValue, i));
  }
 /**
  * This method will increment the unique totals count for the y row identified by yKey.
  *
  * @param yValue identifies the yValue we are keying on, null is valid.
  * @param i the amount to increment the total by, usually 1.
  */
 private void addToYTotal(Object yValue, int i) {
   Number total = (Number) yAxisTotals.get(yValue);
   yAxisTotals.put(yValue, statisticGatherer.getValue(total, i));
 }
 /**
  * This method will increment the unique totals count for the provided xKey.
  *
  * @param xValue identifies the xValue we are keying on, null is valid.
  * @param i the amount to increment the total by, usually 1.
  */
 private void addToXTotal(Object xValue, int i) {
   Number total = (Number) xAxisTotals.get(xValue);
   xAxisTotals.put(xValue, statisticGatherer.getValue(total, i));
 }
 // Adds to irrelevant totals of X for all the passed in Y keys
 void addToXIrrelevantTotals(final Collection yValues, final int incrementValue) {
   for (Object yValue : yValues) {
     Number existingValue = xAxisIrrelevantTotals.get(yValue);
     xAxisIrrelevantTotals.put(yValue, statisticGatherer.getValue(existingValue, incrementValue));
   }
 }
 // Adds to irrelevant totals of Y for all the passed in X keys
 void addToYIrrelevantTotals(final Collection xValues, final int incrementValue) {
   for (Object xValue : xValues) {
     Number existingValue = yAxisIrrelevantTotals.get(xValue);
     yAxisIrrelevantTotals.put(xValue, statisticGatherer.getValue(existingValue, incrementValue));
   }
 }
 /**
  * Increments the total count of unique issues added to this StatsMap.
  *
  * @param i the amount to increment the total by, usually 1.
  */
 private void addToEntireTotal(int i) {
   entireTotal = statisticGatherer.getValue(entireTotal, i);
 }