overlaying different charts

[schmidt]

Hi,
Can anyone tell me ,how to overlay line chart on a vertical bar chart.

[Dmitry Kashin]

Something like this:

ValueAxis timeAxis;
NumberAxis valueAxis;

timeAxis = new HorizontalDateAxis(yLabel);
timeAxis.setAutoRange(true);
valueAxis = new VerticalNumberAxis(xLabel);
valueAxis.setAutoRangeIncludesZero(false);
linePlot = new XYPlot(new TimeSeriesCollection(series), null, null);
indexValuesPlot.setRenderer(new StandardXYItemRenderer(StandardXYItemRenderer.SHAPES_AND_LINES, new TimeSeriesToolTipGenerator()));
barPlot = new XYPlot(new TimeSeriesCollection(serie2), null, null);
limitsPlot.setRenderer(new VerticalXYBarRenderer(0, null));
overlaidChartPlot = new OverlaidXYPlot(yLabel, xLabel);
overlaidChartPlot.setDomainAxis(timeAxis);
overlaidChartPlot.setRangeAxis(valueAxis);
overlaidChartPlot.add(barPlot);
overlaidChartPlot.add(linePlot);

[schmidt]

Thanks Dmitry. But the overlaid plot so created gives null pointer exception when asked to saveChartAsJPEG in ChartUtilities. Any reason for this?