if (dataset instanceof RangeInfo) {
            RangeInfo info = (RangeInfo) dataset;
            return new Double(info.getRangeUpperBound(true));
        }

        // hasn't implemented RangeInfo, so we'll have to iterate...
        else  {

            double maximum = Double.NEGATIVE_INFINITY;
            int seriesCount = dataset.getSeriesCount();
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double value;
                    if (dataset instanceof IntervalXYDataset) {
                        IntervalXYDataset intervalXYData
                            = (IntervalXYDataset) dataset;
                        value = intervalXYData.getEndYValue(series, item);
                    }
                    else if (dataset instanceof OHLCDataset) {
                        OHLCDataset highLowData = (OHLCDataset) dataset;
                        value = highLowData.getHighValue(series, item);
                    }
                    else {
                        value = dataset.getYValue(series, item);
                    }
                    if (!Double.isNaN(value)) {
                        maximum = Math.max(maximum, value);
                    }
                }
            }
            if (maximum == Double.NEGATIVE_INFINITY) {
                return null;
            }
            else {
                return new Double(maximum);