public Number getHigh(int series, int item) {
        return ((OHLCDataset) this.parent).getHigh(this.map[series], item);
    }

    /**
     * Returns the high-value (as a double primitive) for an item within a 
     * series.
     * 
     * @param series  the series (zero-based index).
     * @param item  the item (zero-based index).
     * 
     * @return The high-value.
     */
    public double getHighValue(int series, int item) {
        double result = Double.NaN;
        Number high = getHigh(series, item);
        if (high != null) {
            result = high.doubleValue();   
        }
        return result;