This example shows how to avoid overlapping multiple bars on a double axis by adding a zero sequence in each data set. Following the example, I created four DefaultIntervalCategoryDataset objects, each on its own axis (the full code is given below).
The advantage of adding a zero sequence in each data set is seen in the following figure, for example. Series 2 is stored separately from series 1.
But still, Series 3 overlaps Series 4, and so Series 3 is hidden (by Series 4). I could not find a reason and get a solution.
How to avoid this ovelapping, is there also another alternative method to demonstrate the problem with several categories (at intervals, as in my problem) in a more efficient and convenient way?
public class IntervalBarChartTest extends ApplicationFrame { public IntervalBarChartTest(String title) { super(title); JPanel chartPanel = createDemoPanel(); chartPanel.setPreferredSize(new Dimension(900, 270)); setContentPane(chartPanel); } private static DefaultIntervalCategoryDataset createDataset1() { Number[] series1_Start = new Number[] {25,50}; Number[] series1_End = new Number[] {50,75}; Number[] dymmy1_Start = new Number[] {null,null}; Number[] dummy1_End = new Number[] {null,null}; Number[][] starts = new Number[][]{series1_Start,dymmy1_Start}; Number[][] ends = new Number[][] {series1_End,dummy1_End}; String[] categoryKeys = {"50th%ile", "90th%ile"}; String[] seriesKeys = {"Series1",""}; DefaultIntervalCategoryDataset dataset= new DefaultIntervalCategoryDataset(seriesKeys,categoryKeys,starts, ends); return dataset; } private static DefaultIntervalCategoryDataset createDataset2() { Number[] dymmy1_Start = new Number[] {null,null}; Number[] dummy1_End = new Number[] {null,null}; Number[] series2_Start = new Number[] {150,150}; Number[] series2_End = new Number[] {200,200}; Number[] dymmy3_Start = new Number[] {null,null}; Number[] dummy3_End = new Number[] {null,null}; Number[][] starts = new Number[][]{dymmy1_Start,series2_Start,dymmy3_Start}; Number[][] ends = new Number[][] {dummy1_End,series2_End, dummy3_End}; String[] categoryKeys = {"50th%ile", "90th%ile"}; String[] seriesKeys = {"","Series2",""}; DefaultIntervalCategoryDataset dataset= new DefaultIntervalCategoryDataset(starts, ends); dataset.setSeriesKeys(seriesKeys); dataset.setCategoryKeys(categoryKeys); return dataset; } private static DefaultIntervalCategoryDataset createDataset3() { Number[] dymmy1_Start = new Number[] {null,null}; Number[] dummy1_End = new Number[] {null,null}; Number[] series2_Start = new Number[] {150,150}; Number[] series2_End = new Number[] {200,200}; Number[] dymmy2_Start = new Number[] {null,null}; Number[] dummy2_End = new Number[] {null,null}; Number[][] starts = new Number[][]{dymmy1_Start,series2_Start,dymmy2_Start}; Number[][] ends = new Number[][] {dummy1_End,series2_End,dummy2_End}; String[] categoryKeys = {"50th%ile", "90th%ile"}; String[] seriesKeys = {"","Series3",""}; DefaultIntervalCategoryDataset dataset= new DefaultIntervalCategoryDataset(starts, ends); dataset.setSeriesKeys(seriesKeys); dataset.setCategoryKeys(categoryKeys); return dataset; } private static DefaultIntervalCategoryDataset createDataset4() { Number[] dymmy1_Start = new Number[] {null,null}; Number[] dummy1_End = new Number[] {null,null}; Number[] series2_Start = new Number[] {50,50}; Number[] series2_End = new Number[] {100,100}; Number[][] starts = new Number[][]{dymmy1_Start,series2_Start}; Number[][] ends = new Number[][] {dummy1_End,series2_End, }; String[] categoryKeys = {"50th%ile", "90th%ile"}; String[] seriesKeys = {"","Series4"}; DefaultIntervalCategoryDataset dataset= new DefaultIntervalCategoryDataset(starts, ends); dataset.setSeriesKeys(seriesKeys); dataset.setCategoryKeys(categoryKeys); return dataset; } private static JFreeChart createChart(CategoryDataset dataset1, CategoryDataset dataset2, CategoryDataset dataset3,CategoryDataset dataset4) { CategoryAxis domainAxis = new CategoryAxis("Percentiles"); NumberAxis rangeAxis = new NumberAxis("ms1"); IntervalBarRenderer renderer = new IntervalBarRenderer(); rendererSettings(renderer); //CategoryPlot plot = new CategoryPlot(dataset1, domainAxis, rangeAxis,renderer); final CategoryPlot plot = new CategoryPlot(dataset1, domainAxis, rangeAxis, renderer) { /** * Override the getLegendItems() method to handle special case. * * @return the legend items. */ public LegendItemCollection getLegendItems() { final LegendItemCollection result = new LegendItemCollection(); final CategoryDataset data = getDataset(); if (data != null) { final CategoryItemRenderer r = getRenderer(); if (r != null) { final LegendItem item = r.getLegendItem(0, 0); result.add(item); } } // the JDK 1.2.2 compiler complained about the name of this // variable final CategoryDataset dset2 = getDataset(1); if (dset2 != null) { final CategoryItemRenderer renderer2 = getRenderer(1); if (renderer2 != null) { final LegendItem item = renderer2.getLegendItem(1, 1); result.add(item); } } final CategoryDataset dset3 = getDataset(2); if (dset3 != null) { final CategoryItemRenderer renderer2 = getRenderer(2); if (renderer2 != null) { final LegendItem item = renderer2.getLegendItem(2, 1); result.add(item); } } final CategoryDataset dset4 = getDataset(3); if (dset4 != null) { final CategoryItemRenderer renderer2 = getRenderer(3); if (renderer2 != null) { final LegendItem item = renderer2.getLegendItem(3, 1); result.add(item); } } return result; } }; /////////// JFreeChart chart = new JFreeChart("Percentiles", plot); // final CategoryPlot plot2 = chart.getCategoryPlot(); // CategoryAxis axis = plot2.getDomainAxis(); // final CategoryDataset dataset2 = createDataset2(); plot.setDataset(1, dataset2); plot.mapDatasetToRangeAxis(1, 1); final ValueAxis axis2 = new NumberAxis("ms2"); plot.setRangeAxis(1, axis2); IntervalBarRenderer renderer2 = new IntervalBarRenderer(); rendererSettings(renderer2); plot.setRenderer(1, renderer2); plot.setDataset(2, dataset3); plot.mapDatasetToRangeAxis(2, 2); final ValueAxis axis3 = new NumberAxis("ms3"); plot.setRangeAxis(2, axis3); IntervalBarRenderer renderer3 = new IntervalBarRenderer(); rendererSettings(renderer3); plot.setRenderer(2, renderer3); plot.setDataset(3, dataset4); plot.mapDatasetToRangeAxis(3, 3); final ValueAxis axis4 = new NumberAxis("ms4"); plot.setRangeAxis(3, axis4); IntervalBarRenderer renderer4 = new IntervalBarRenderer(); rendererSettings(renderer4); plot.setRenderer(3, renderer4); ChartUtilities.applyCurrentTheme(chart); return chart; } private static void rendererSettings(IntervalBarRenderer renderer){ // renderer.setItemLabelFont(new Font("Verdana",Font.PLAIN,2)); // renderer.setBaseItemLabelGenerator(new IntervalCategoryItemLabelGenerator()); // renderer.setBasePositiveItemLabelPosition(new ItemLabelPosition(ItemLabelAnchor.INSIDE6, TextAnchor.BOTTOM_CENTER)); // renderer.setItemMargin(0.3); renderer.setBaseItemLabelsVisible(true); } public static JPanel createDemoPanel() { JFreeChart chart = createChart(createDataset1(),createDataset2(),createDataset3(),createDataset4()); return new ChartPanel(chart); } public static void main(String[] args) { JFrame demo = new IntervalBarChartTest( "Testing"); demo.pack(); RefineryUtilities.centerFrameOnScreen(demo); demo.setVisible(true); } }