Read data from CSV file into ArrayList and display in XY Chart

Question

I would like to display a temperature curve over time. I have now read a file, which is CSV-similar, that let me know the time and the temperature indicated. Now I want to u

Answer 1

Several problems are evident:

• You never add anything to lines; at a minimum, you'll need something like this:

  lines.add(line);
  

• Instead of ChartFactory.createXYLineChart(), consider creating a time series:

  ChartFactory.createTimeSeriesChart(…)
  

• The XYDataset returned by createDataset() should be a TimeSeriesCollection to which you add a TimeSeries.

• In createDataset(), iterate though lines, parse the data fields, and add the values to the TimeSeries.

• The time values given are most closely modeled by LocalTime, but TimeSeries expects to add() coordinates defined by a RegularTimePeriod and a double; see Legacy Date-Time Code concerning the conversion shown below.

• Note that TimeSeries throws SeriesException for duplicate domain values; as a result, only three of the four lines int eh sample input air charted.

• Instead of replacing the factory supplied XYLineAndShapeRenderer, get a reference to it for later modification.

• Alter the chart's size using one of the approaches shown here.

• Avoid extending top-level containers line ApplicationFrame.

• Construct and manipulate Swing GUI objects only on the event dispatch thread.

• Use a try-with-resources statement to ensure that each resource is closed at the end of the statement.

• As your actual data contains ISO 8601 dates, ZonedDateTime.parse() can be used directly; use setDateFormatOverride() to format the date axis labels; the example below specifies a UTC time zone in ISO 8601 format for easy comparison; comment out the call to setDateFormatOverride() to see the times in your local time zone.

import java.awt.Color;
import java.awt.EventQueue;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.time.ZonedDateTime;
import java.util.Date;
import java.util.TimeZone;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.general.SeriesException;
import org.jfree.data.time.Second;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.ApplicationFrame;

/** @see https://stackoverflow.com/a/45173688/230513 */
public class CSVTest {

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            ApplicationFrame frame = new ApplicationFrame("CSVTest");
            CSVTest test = new CSVTest();
            frame.add(test.createChart("Temperature profile"));
            frame.pack();
            frame.setLocationRelativeTo(null);;
            frame.setVisible(true);
        });
    }

    private ChartPanel createChart(String chartTitle) {
        JFreeChart chart = ChartFactory.createTimeSeriesChart(chartTitle,
            "Time", "Temperature", createDataset(), true, true, false);
        ChartPanel chartPanel = new ChartPanel(chart);
        XYPlot plot = chart.getXYPlot();
        plot.setBackgroundPaint(Color.WHITE);
        XYLineAndShapeRenderer r = (XYLineAndShapeRenderer) plot.getRenderer();
        r.setBaseShapesVisible(true);
        DateAxis axis = (DateAxis) plot.getDomainAxis();
        SimpleDateFormat df = new SimpleDateFormat("HH:mm:ssX");
        df.setTimeZone(TimeZone.getTimeZone("UTC"));
        axis.setDateFormatOverride(df);
        return chartPanel;
    }

    private XYDataset createDataset() {
        TimeSeries series = new TimeSeries("Temperature");
        TimeSeriesCollection dataset = new TimeSeriesCollection(series);
        try (FileReader fr = new FileReader("temp.csv");
            BufferedReader br = new BufferedReader(fr)) {
            String line;
            while ((line = br.readLine()) != null) {
                String[] s = line.split(",");
                ZonedDateTime zdt = ZonedDateTime.parse(s[0]);
                Second second = new Second(Date.from(zdt.toInstant()));
                series.add(second, Double.valueOf(s[2]));
            }
        } catch (IOException | SeriesException e) {
            System.err.println("Error: " + e);
        }
        return dataset;
    }
}