How do I show rainfall index along with temperature on my JFreeChart TimeSeries chart?

Question

Currently, my TimeSeries graph shows the temperature of a location every 2 seconds.
Now, if I want to show the rainfall index along with the temperature every 2 seconds, how

Answer 1

As noted here, a TimeSeriesCollection can display more than one series. Simply add both series to the collection and update each series in your timer's ActionListener. In the example below, setMaximumItemAge() is also invoked on each TimeSeries, as shown here, to discard older data. To accommodate different units, you can set multiple axes on the same plot, as shown here.

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.*;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.Timer;
import org.jfree.chart.*;
import org.jfree.data.time.Second;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;

/** @See https://stackoverflow.com/q/44037591/230513 */
public class ChartPanelTest {

    private static final Random R = new Random();
    private static final int AGE = 60;

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            JFrame f = new JFrame();
            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            TimeSeriesCollection dataset = new TimeSeriesCollection();
            TimeSeries series1 = new TimeSeries("T1");
            series1.setMaximumItemAge(AGE);
            dataset.addSeries(series1);
            TimeSeries series2 = new TimeSeries("T2");
            series2.setMaximumItemAge(AGE);
            dataset.addSeries(series2);
            JFreeChart chart = ChartFactory.createTimeSeriesChart(
                "Test", "Time", "Value", dataset, false, false, false);
            ChartPanel chartPanel = new ChartPanel(chart) {
                @Override
                public Dimension getPreferredSize() {
                    return new Dimension(640, 480);
                }
            };
            f.add(chartPanel);
            Timer timer = new Timer(2000, new ActionListener() {
                Second s = new Second();
                { for (int i = 0; i < AGE; i++) actionPerformed(null); }
                @Override
                public void actionPerformed(ActionEvent e) {
                    series1.add(s, R.nextGaussian());
                    series2.add(s, R.nextGaussian());
                    s = (Second) s.next().next();
                }
            });
            timer.start();
            f.pack();
            f.setLocationRelativeTo(null);
            f.setVisible(true);
        });
    }
}