java - Using Multiple Renderers in JFreechart

Question

I have data that I'd like to represent as a box and whiskers graph, and have set up a category plot to do so. However, in addition, I'd like to add a line chart that shows an accumulation of the averages for each data point.

Right now my code is something like this

DefaultBoxAndWhiskerCategoryDataset dataSet = new DefaultBoxAndWhiskerCategoryDataset();
int i = 0;
for (List<Integer> categoryList : categoryLists) {
    dataSet.add(categoryList, i, "BoxAndWhiskers");
    i++;
}
BoxAndWhiskerRenderer renderer = new BoxAndWhiskerRenderer();

double sum = 0;
i = 0;
DefaultCategoryDataset averageDataSet = new DefaultCategoryDataset();
for (double average : averages) {
    sum += average;
    averageDataSet.add(sum, i, "Average");
    i++;
}
LineAndShapeRenderer lineAndShapeRenderer = new LineAndShapeRenderer();


CategoryAxis xAxis = new CategoryAxis("Type");
NumberAxis yAxis = new NumberAxis("Value");
CategoryPlot plot = new CategoryPlot(dataSet, xAxis, yAxis, renderer);

plot.setDataset(1, averageDataSet);
plot.setRenderer(1, lineAndShapeRenderer);

JFreeChart chart = new JFreeChart(
    "Box-and-Whisker",
    new Font("SansSerif", Font.BOLD, 14),
    plot,
    true
);

BufferedImage outputImage = chart.createBufferedImage(800, 600);

ImageIO.write(outputImage, "png", new File("output.png"));

However, when I look at my output.png, I only see the box and whiskers render (no lineandshape graph).

Is there something else I need to do to use both renderers and datasets in my output image? Additionally, is there a better approach to getting a cumuluative line for the averages in my box and whiskers graph?

Answer 1

I'm trying to figure out how to lay the points on top of the box and whiskers points properly.

As shown here for CategoryDataset, each rowKey is a series and each columnKey is an element in the series. In the example below, the "Mean" row of catData includes an entry for each columnKey in boxData. Use setDatasetRenderingOrder() to specify DatasetRenderingOrder.

import java.awt.Dimension;
import java.awt.EventQueue;
import java.util.Arrays;
import javax.swing.JFrame;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.DatasetRenderingOrder;
import org.jfree.chart.renderer.category.BoxAndWhiskerRenderer;
import org.jfree.chart.renderer.category.LineAndShapeRenderer;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.statistics.DefaultBoxAndWhiskerCategoryDataset;

/**
 * @see https://stackoverflow.com/a/38242696/230513
 */
public class Test {

    private void display() {
        JFrame f = new JFrame("Test");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        DefaultBoxAndWhiskerCategoryDataset boxData = new DefaultBoxAndWhiskerCategoryDataset();
        boxData.add(Arrays.asList(30, 36, 46, 55, 65, 76, 81, 80, 71, 59, 44, 34), "Planet", "Endor");
        boxData.add(Arrays.asList(22, 25, 34, 44, 54, 63, 69, 67, 59, 48, 38, 28), "Planet", "Hoth");
        BoxAndWhiskerRenderer boxRenderer = new BoxAndWhiskerRenderer();
        DefaultCategoryDataset catData = new DefaultCategoryDataset();
        catData.addValue(boxData.getMeanValue(0, 0), "Mean", boxData.getColumnKey(0));
        catData.addValue(boxData.getMeanValue(0, 1), "Mean", boxData.getColumnKey(1));
        LineAndShapeRenderer lineRenderer = new LineAndShapeRenderer();
        CategoryAxis xAxis = new CategoryAxis("Type");
        NumberAxis yAxis = new NumberAxis("Value");
        yAxis.setAutoRangeIncludesZero(false);
        CategoryPlot plot = new CategoryPlot(boxData, xAxis, yAxis, boxRenderer);
        plot.setDataset(1, catData);
        plot.setRenderer(1, lineRenderer);
        plot.setDatasetRenderingOrder(DatasetRenderingOrder.FORWARD);
        JFreeChart chart = new JFreeChart("Test", JFreeChart.DEFAULT_TITLE_FONT, plot, true);
        f.add(new ChartPanel(chart){
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(320, 480);
            }
        });
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Test()::display);
    }
}