public Range getDataRange(ValueAxis axis) {
        Range l_result = null;
        Iterator l_itr = getSubplots().iterator();
        while (l_itr.hasNext()) {
            XYPlot l_subplot = (XYPlot) l_itr.next();

            l_result = Range.combine(l_result, l_subplot.getDataRange(axis));
        }
        return l_result;