Dynamic Histogram JFreeChart

Question

I have class Histogram and I would love to update his vaules over time. Could you tell me how to do it with timer? :P I just have 4 bins all the time. Additionaly I have thread in which I change Calculation.n over time is it possible to lock thread until histogram is updated? Although I dont need to do it on timer I just want everytime "n" changes its value histogram to be updated.

public class Histogram extends JPanel  {

/**
 * 
 */
private static final long serialVersionUID = 8582587439869049160L;



public Histogram() {
    // TODO Auto-generated constructor stub
    setVisible(true);
    final HistogramDataset dataSet = new HistogramDataset();
    final double particles[] = {Calculation.n,Calculation.n1,Calculation.n2,Calculation.n3};
    dataSet.addSeries("How many particles passed", particles, 4);

     Timer timer = new Timer(250, null);
     timer.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {

            }
        });
     timer.start();


    JFreeChart histogram =ChartFactory.createHistogram(
            "Histogram",
            null,
            null,
            dataSet,
            PlotOrientation.VERTICAL,
            true,
            true,
            false);
    ChartPanel chartPanel = new ChartPanel(histogram);
    add(chartPanel);
    revalidate();


}

Answer 1

There is an alternative dataset implementation included in JFreeChart: SimpleHistogramDataset. This one allows you to keep adding new values (via the addObservation()/addObservations() methods).

Answer 2

I don't think this is possible without implementing your own version of HistogramDataset, as then histogram is evaluated when a dataset is added.

If you do implement your own version of HistogramDataset, base your code on HistogramDataset #addSeries and remember to call fireDatasetChanged() at the end.