David Gilbert

JFreeChart and OpenCSV

2020-11-21T00:00:00+00:00

A developer that uses JFreeChart asked me how they should go about using it with data from a CSV file (that is, a text file containing a table of comma-separated values). There are many different approaches that could be taken, so here I will give one example that makes use of the OpenCSV project. We are going to create a chart showing excess death statistics by country during the COVID19 crisis (the source of the data is https://ourworldindata.org/excess-mortality-covid). The end result looks like this:

We will use the latest release of Java (version 15) to create a Maven-driven modular Java application that outputs the chart in SVG format using JFreeSVG. This, of course, requires that you have Maven installed on your computer (at the time of writing, the latest version is 3.6.3).

To begin, create a working directory (name it however you like) and switch to that directory:

$ mkdir working
$ cd working

Next, go to https://ourworldindata.org/excess-mortality-covid and download the excess-mortality-p-scores.csv file to the working directory (to download the data, scroll down the web page to the section “Excess mortality for all ages” then click the Download tab beneath the chart on the right hand side, you should then see a blue button for downloading the CSV data). If you are curious, you can open this file with a text editor (or a spreadsheet program) and take a look at the data. Our goal is to read this data and create a chart that lets us visualise it easily.

We can now start creating the Maven project and our Java source files. The first step is to create a project file (pom.xml) for Maven, to describe the application we will create, its dependencies and the versions of the Maven plugins that we want to use. The file should be created at the top level in the working directory, and looks like this:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.jfree</groupId>
    <artifactId>jfreechart-csv-demo</artifactId>
    <version>1.0</version>

    <name>jfreechart-csv-demo</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>15</maven.compiler.source>
        <maven.compiler.target>15</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.opencsv</groupId>
            <artifactId>opencsv</artifactId>
            <version>5.3</version>
        </dependency>
        <dependency>
            <groupId>org.jfree</groupId>
            <artifactId>jfreechart</artifactId>
            <version>1.5.1</version>
        </dependency>
        <dependency>
            <groupId>org.jfree</groupId>
            <artifactId>org.jfree.svg</artifactId>
            <version>4.1</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-clean-plugin</artifactId>
                <version>3.1.0</version>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>${maven.compiler.source}</source>
                    <target>${maven.compiler.target}</target>
                    <encoding>${project.build.sourceEncoding}</encoding>                
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                    <encoding>${project.build.sourceEncoding}</encoding>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.2.0</version>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>org.jfree.chart.demo.csv.App</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>3.1.2</version>
                <executions>
                    <execution>
                        <id>copy-dependencies</id>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-dependencies</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

If you are not very familiar with Maven, don’t focus too much on the details in the pom.xml for now. The most important section is the dependencies, where we have declared that we want to use OpenCSV version 5.3, JFreeChart version 1.5.1 and JFreeSVG version 4.1. Later when we build the project, Maven will download these dependencies automatically.

The plugin section is related to Maven itself and controls the versions of plugins that will be used by Maven when we build our application. There is also an important detail in the configuration for the maven-jar-plugin, where we’ve specified the name of the main class for the application. This will add some info to the jar file to make it simpler to run the application once it is complete.

Now let’s move on to creating the source files for our Java application. Maven expects to find project files arranged in a certain way, so we will first create a directory to contain the Java application source code, by convention src/main/java:

$ mkdir -p src/main/java

Now switch to the java directory:

$ cd src/main/java

Recall that we said we will create a modular Java application. This means we need to define the name of the module for the demo application and list the modules that our application will depend upon (the same dependencies we already set up in Maven, plus a couple of modules that ship with the JDK itself). This is done with the following module-info.java file (create this within the src/main/java directory):

module opencsvdemo {
    requires opencsv;
    requires org.jfree.jfreechart;
    requires org.jfree.svg;
    requires java.desktop;
    requires java.sql;
    exports org.jfree.chart.csv;
}

The module name is opencsvdemo. If you plan to distribute a Java module (whether it be an application or an API) you should ensure that the module name is unique. We don’t need to worry so much about that here, since our demo is a “throw-away” project. You can read some more about that in this post at Stack Overflow: https://stackoverflow.com/questions/43192741/how-should-i-name-my-java-9-module.

The first two modules required are opencsv and org.jfree.jfreechart. These are not yet fully modular libraries but, rather, Java 8 jar files. However, the Java module system can import these jars as “automatic modules”. The third module listed is org.jfree.svg is the JFreeSVG library. This library is a first-class Java module, because the JFreeSVG jar file contains module information inside it.

Our application will also require the modules java.desktop and java.sql from the JDK (the latter is a consequence of some features in OpenCSV that we won’t be using).

With these formalities out of the way, we can begin working on the Java classes (just two of them) required for our application. The first is a Java class that will be used by OpenCSV to store one data item (or row) from the CSV file. I’ve called this ExcessMortalityBean.java, and created it in the org.jfree.chart.demo.csv package. This class has one attribute per column in the data file.

From within the src/main/java directory, create the subdirectories required for the package (if you are using a Java integrated development environment (IDE), it will take care of this for you):

$ mkdir -p org/jfree/chart/demo/csv
$ cd org/jfree/chart/demo/csv

Now create the following file, ExcessMortalityBean.java. Notice in the source file how the attributes are annotated to inform OpenCSV how it should read the data from the CSV into instances of this bean class:

package org.jfree.chart.demo.csv;

import java.time.LocalDate;
import com.opencsv.bean.CsvBindByName;
import com.opencsv.bean.CsvDate;

/**
 * Bean class for recording excess mortality data from 
 * https://ourworldindata.org/excess-mortality-covid
 * 
 * Includes annotations to configure for OpenCSV to read the data file.
 */
public class ExcessMortalityBean {

    @CsvBindByName
    private String entity;

    @CsvBindByName
    private String code;

    @CsvDate("yyyy-MM-dd")
    @CsvBindByName(column="Date")
    private LocalDate date;

    @CsvBindByName(column = "Excess mortality P-scores, all ages")
    private double excessPercent;

    public ExcessMortalityBean() {
    }

    public String getEntity() {
        return entity;
    }

    public void setEntity(String entity) {
        this.entity = entity;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public LocalDate getDate() {
        return date;
    }

    public void setDate(LocalDate date) {
        this.date = date;
    }

    public double getExcessPercent() {
        return excessPercent;
    }

    public void setExcessPercent(double excessPercent) {
        this.excessPercent = excessPercent;
    }

}

We will create a second class, App.java that contains the main application code. We’ve put everything in the main() method, which isn’t how you would structure a larger Java application but for the purposes of a demo it lets us focus on just the essential code:

package org.jfree.chart.demo.csv;

import com.opencsv.bean.CsvToBeanBuilder;
import java.awt.BasicStroke;
import java.awt.Rectangle;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.time.LocalDate;
import java.util.List;
import java.util.Arrays;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.StandardChartTheme;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.chart.title.TextTitle;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.Day;
import org.jfree.chart.ChartUtils;
import org.jfree.svg.SVGGraphics2D;
import org.jfree.svg.SVGUtils;

/**
 * App that produces a chart from CSV data.
 */
public class App {

    private static final String FILENAME = "excess-mortality-p-scores.csv";

    /**
     * Entry point for the application.
     * 
     * @param args  ignored.
     * 
     * @throws FileNotFoundException
     * @throws IOException 
     */
    public static void main(String[] args) throws FileNotFoundException, IOException {

        // read the CSV file
        System.out.println("Reading the file " + FILENAME);
        FileReader fileReader = new FileReader(FILENAME);
        List<ExcessMortalityBean> excessMortalityList = new CsvToBeanBuilder(fileReader)
                .withType(ExcessMortalityBean.class).build().parse();

        // move the data into a JFreeChart dataset
        System.out.println("Creating a JFreeChart dataset from a subset of the data");
        List<String> countries = Arrays.asList("CAN", "CHE", "FRA", "ITA", "LTU", "NZL");
        TimeSeriesCollection dataset = new TimeSeriesCollection();
        for (ExcessMortalityBean bean : excessMortalityList) {
            String country = bean.getCode();
            if (!countries.contains(country)) continue;
            TimeSeries series = dataset.getSeries(country);
            if (series == null) {
                series = new TimeSeries(country);
                dataset.addSeries(series);
            }
            LocalDate day = bean.getDate();
            series.addOrUpdate(new Day(day.getDayOfMonth(), day.getMonthValue(), day.getYear()), bean.getExcessPercent());
        }

        // configure JFreeChart for displaying the data
        System.out.println("Setting up JFreeChart");
        JFreeChart chart = ChartFactory.createTimeSeriesChart(
            "Excess Mortality By Country", "Date", "Excess Mortality (%)", dataset);
        chart.addSubtitle(new TextTitle("Source: https://ourworldindata.org/excess-mortality-covid"));
        XYPlot plot = (XYPlot) chart.getPlot();
        XYLineAndShapeRenderer renderer = (XYLineAndShapeRenderer) plot.getRenderer();
        renderer.setAutoPopulateSeriesStroke(false);
        renderer.setDefaultStroke(new BasicStroke(3.0f));
        StandardChartTheme.createDarknessTheme().apply(chart);

        // render to chart to a PNG file
        System.out.println("Rendering the chart to a PNG file");
        ChartUtils.saveChartAsPNG(new File("chart.png"), chart, 1000, 640);

        // render the chart to an SVG file
        System.out.println("Rendering the chart to a SVG file");
        SVGGraphics2D g2 = new SVGGraphics2D(720, 480);
        chart.draw(g2, new Rectangle(720, 480));
        //SVGUtils.writeToHTML(new File("svg.html"), "JFreeChart CSV Demo", g2.getSVGElement());
        SVGUtils.writeToSVG(new File("chart.svg"), g2.getSVGElement());
    }

}

The comments in the source code describe what each section of the code is doing, starting with reading the CSV file (using OpenCSV), creating a dataset for JFreeChart, configuring the chart instance, then rendering the chart as both a PNG image file and a Scalable Vector Graphics (SVG) file.

Now that everything is in place, we can use Maven to build our application. Switch back to the working directory, the location of the pom.xml file, and type the following command to trigger a Maven build:

$ mvn clean package

Assuming this worked without errors, we can run our application using Java (specifying the module path and module to run) as follows:

$ java --module-path target/jfreechart-csv-demo-1.0.jar:target/dependency -m opencsvdemo

As the program runs, it will produce the following output on the console:

Reading the file excess-mortality-p-scores.csv
Creating a JFreeChart dataset from a subset of the data
Setting up JFreeChart
Rendering the chart to a PNG file
Rendering the chart to a SVG file

After the program completes, you will find two new files in the working directory, a PNG and an SVG version of the chart. If you open the SVG file with a web-browser, you will see the chart shown at the top of this post.

Congratulations on creating a modular Java application with OpenCSV, JFreeChart and JFreeSVG!

Open Source Libraries - Current Versions

2020-11-16T00:00:00+00:00

I’m maintaining a number of open source Java libraries on Github. I have created modular versions for all of them, except JFreeChart (which will take some more time). Here is a summary of the latest version numbers, with the non-modular versions in the JDK8+ column and the modular versions in the JDK11+ column.

Library	Description	JDK8+ (non-modular)	JDK11+ (modular)
JFreeChart	Chart library for the Java platform	1.5.1	tbd
JFreeChart-FX	JFreeChart extension for JavaFX	1.0.1	2.0
FXGraphics2D	Bridge from Java2D to JavaFX	1.8	2.1
JFreeSVG	SVG Graphics2D implementation	3.4	4.1
OrsonPDF	PDF Graphics2D implementation	1.9	JFreePDF
JFreePDF	PDF Graphics2D implementation	OrsonPDF	2.0
Orson Charts	3D chart library	1.7	2.0
Orson Charts FX	Orson Charts extension for JavaFX	1.0	2.0

I encourage people to use the modular versions of the libraries, but for those still using Java 8 the non-modular versions are still current.

Eclipse and JFreeChart

2018-04-14T00:00:00+00:00

Today I downloaded the latest Eclipse (Oxygen 3A) release because a customer is asking about getting started with JFreeChart and Eclipse, and the existing instructions for that are a bit out of date. Here are some new instructions for getting started.

Start Eclipse, then select New -> Project... from the File menu. Under the Wizards selection, choose Maven Project, then click the Next button. When the New Maven Project dialog appears, select the ‘Create a simple project’ checkbox, then click the Next button. At the next step, fill in the details that will be used to set up the initial pom.xml file that will be used by Maven to build your application (you can change the details later), then click the Finish button. At this point you will have a skeleton project that looks like this: Now you need to edit the pom.xml to include a dependency for JFreeChart 1.5.0. Add the lines 8 - 14 shown in the screenshot below:

Next, you need to add the code for a simple JFreeChart application. Right-click on src/main/java and select the New -> Class menu item. Type ‘First’ as the name of the class and then click the Finish button.

Next you should edit the First.java file to contain the following code:

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartFrame;
import org.jfree.chart.JFreeChart;
import org.jfree.data.general.DefaultPieDataset;

/**
 * A simple introduction to using JFreeChart. This demo is described in the
 * JFreeChart Developer Guide.
 */
public class First {
    
    /**
     * The starting point for the demo.
     *
     * @param args ignored.
     */
    public static void main(String[] args) {
        // create a dataset...
        DefaultPieDataset data = new DefaultPieDataset();
        data.setValue("Category 1", 43.2);
        data.setValue("Category 2", 27.9);
        data.setValue("Category 3", 79.5);
        // create a chart...
        JFreeChart chart = ChartFactory.createPieChart(
            "Sample Pie Chart",
            data,
            true, // legend?
            true, // tooltips?
            false // URLs?
        );
        // create and display a frame...
        ChartFrame frame = new ChartFrame("First", chart);
        frame.pack();
        frame.setVisible(true);
    }
}

Now clicking the Run button in Eclipse will run the app and show you the following:

And it is as simple as that!

OrsonPDF and iText

2017-12-12T00:00:00+00:00

I created OrsonPDF a few years ago because I wanted a lightweight API for exporting charts (JFreeChart and Orson Charts) to PDF files. The approach used is to implement the Graphics2D API (from Java2D), and under the hood write the code that generates the corresponding PDF bytes. This works really well, and the resulting jar file is around 67kb, which I would classify as lightweight.

At the time, the main PDF library in the Java space (iText) had a PdfGraphics2d class that did the same job (iText also has many other things, of course - check it out if you need to do serious PDF work in Java). I noticed, however, that recent releases of iText have dropped the PdfGraphics2d class, which has left a few JFreeChart users stuck - for example:

https://stackoverflow.com/questions/47593083/migrating-jfreechart-from-itext-5-to-7

So, while I’m no iText expert, I wondered if it would be possible to combine the PDFGraphics2D implementation in OrsonPDF to render a chart into a PDF document created using iText. It turns out that this is possible and (as far as I can tell) works pretty well. Here’s a screenshot of the resulting PDF, the code follows:

And now the code (dependencies listed afterwards):

package com.orsonpdf.demo;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Rectangle;
import java.io.ByteArrayInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfReader;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.xobject.PdfFormXObject;
import com.itextpdf.layout.Document;
import com.itextpdf.layout.element.Image;
import com.itextpdf.layout.element.Paragraph;
import com.orsonpdf.PDFDocument;
import com.orsonpdf.PDFGraphics2D;
import com.orsonpdf.Page;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.block.BlockBorder;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.chart.title.TextTitle;
import org.jfree.chart.ui.HorizontalAlignment;
import org.jfree.data.time.Month;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;

/**
 * Creates a PDF document with iText, then inserts a PDF chart generated with
 * JFreeChart and OrsonPDF.
 */
public class ITextPDFWithChart {

    private static byte[] generateChartPDF() {
        // here we use OrsonPDF to generate PDF in a byte array
        PDFDocument doc = new PDFDocument();
        Rectangle bounds = new Rectangle(500, 335);
        Page page = doc.createPage(bounds);
        PDFGraphics2D g2 = page.getGraphics2D();
        JFreeChart chart = createChart(createDataset());
        chart.draw(g2, bounds);
        return doc.getPDFBytes();
    }
    
    /**
     * Creates a chart.
     *
     * @param dataset  a dataset.
     *
     * @return A chart.
     */
    private static JFreeChart createChart(XYDataset dataset) {

        JFreeChart chart = ChartFactory.createTimeSeriesChart(
            "International Coffee Organisation : Coffee Prices",
            null, "US cents/lb", dataset);

        String fontName = "Serif";
        chart.getTitle().setFont(new Font(fontName, Font.BOLD, 18));
        chart.addSubtitle(new TextTitle(
                "Source: http://www.ico.org/historical/2010-19/PDF/HIST-PRICES.pdf", 
                new Font(fontName, Font.PLAIN, 14)));

        XYPlot plot = (XYPlot) chart.getPlot();
        plot.setDomainPannable(true);
        plot.setRangePannable(false);
        plot.setDomainCrosshairVisible(true);
        plot.setRangeCrosshairVisible(true);
        plot.getDomainAxis().setLowerMargin(0.0);
        plot.getDomainAxis().setLabelFont(new Font(fontName, Font.BOLD, 14));
        plot.getDomainAxis().setTickLabelFont(new Font(fontName, Font.PLAIN, 10));
        plot.getRangeAxis().setLabelFont(new Font(fontName, Font.BOLD, 14));
        plot.getRangeAxis().setTickLabelFont(new Font(fontName, Font.PLAIN, 10));
        plot.setRangeGridlinePaint(Color.GRAY);
        plot.setDomainGridlinePaint(Color.GRAY);
        chart.getLegend().setItemFont(new Font(fontName, Font.PLAIN, 14));
        chart.getLegend().setFrame(BlockBorder.NONE);
        chart.getLegend().setHorizontalAlignment(HorizontalAlignment.CENTER);
        XYItemRenderer r = plot.getRenderer();
        if (r instanceof XYLineAndShapeRenderer) {
            XYLineAndShapeRenderer renderer = (XYLineAndShapeRenderer) r;
            renderer.setDefaultShapesVisible(false);
            renderer.setDrawSeriesLineAsPath(true);
            // set the default stroke for all series
            renderer.setAutoPopulateSeriesStroke(false);
            renderer.setDefaultStroke(new BasicStroke(3.0f, 
                    BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL), false);
            renderer.setSeriesPaint(0, Color.RED);
            renderer.setSeriesPaint(1, new Color(24, 123, 58));
            renderer.setSeriesPaint(2, new Color(149, 201, 136));
            renderer.setSeriesPaint(3, new Color(1, 62, 29));
            renderer.setSeriesPaint(4, new Color(81, 176, 86));
            renderer.setSeriesPaint(5, new Color(0, 55, 122));
            renderer.setSeriesPaint(6, new Color(0, 92, 165));
        }

        return chart;

    }

    /**
     * Creates a dataset, consisting of two series of monthly data.
     *
     * @return the dataset.
     */
    private static XYDataset createDataset() {

        TimeSeries s1 = new TimeSeries("Indicator Price");
        s1.add(new Month(1, 2010), 126.80);
        s1.add(new Month(2, 2010), 123.37);
        s1.add(new Month(3, 2010), 125.30);
        s1.add(new Month(4, 2010), 126.89);
        s1.add(new Month(5, 2010), 128.10);
        s1.add(new Month(6, 2010), 142.20);
        s1.add(new Month(7, 2010), 153.41);
        s1.add(new Month(8, 2010), 157.46);
        s1.add(new Month(9, 2010), 163.61);
        s1.add(new Month(10, 2010), 161.56);
        s1.add(new Month(11, 2010), 173.90);
        s1.add(new Month(12, 2010), 184.26);
        s1.add(new Month(1, 2011), 197.35);
        s1.add(new Month(2, 2011), 216.03);
        s1.add(new Month(3, 2011), 224.33);
        s1.add(new Month(4, 2011), 231.24);
        s1.add(new Month(5, 2011), 227.97);
        s1.add(new Month(6, 2011), 215.58);
        s1.add(new Month(7, 2011), 210.36);
        s1.add(new Month(8, 2011), 212.19);
        s1.add(new Month(9, 2011), 213.04);
        s1.add(new Month(10, 2011), 193.90);
        s1.add(new Month(11, 2011), 193.66);
        s1.add(new Month(12, 2011), 189.02);
        s1.add(new Month(1, 2012), 188.90);
        s1.add(new Month(2, 2012), 182.29);
        s1.add(new Month(3, 2012), 167.77);
        s1.add(new Month(4, 2012), 160.46);
        s1.add(new Month(5, 2012), 157.68);
        s1.add(new Month(6, 2012), 145.31);
        s1.add(new Month(7, 2012), 159.07);
        s1.add(new Month(8, 2012), 148.50);
        s1.add(new Month(9, 2012), 151.28);
        s1.add(new Month(10, 2012), 147.12);
        s1.add(new Month(11, 2012), 136.35);
        s1.add(new Month(12, 2012), 131.31);
        s1.add(new Month(1, 2013), 135.38);
        s1.add(new Month(2, 2013), 131.51);
        s1.add(new Month(3, 2013), 131.38);

        TimeSeries s2 = new TimeSeries("Columbian Milds");
        s2.add(new Month(1, 2010), 207.51);
        s2.add(new Month(2, 2010), 204.71);
        s2.add(new Month(3, 2010), 205.71);
        s2.add(new Month(4, 2010), 200.00);
        s2.add(new Month(5, 2010), 200.54);
        s2.add(new Month(6, 2010), 224.49);
        s2.add(new Month(7, 2010), 235.52);
        s2.add(new Month(8, 2010), 243.98);
        s2.add(new Month(9, 2010), 247.77);
        s2.add(new Month(10, 2010), 230.02);
        s2.add(new Month(11, 2010), 244.02);
        s2.add(new Month(12, 2010), 261.97);
        s2.add(new Month(1, 2011), 279.88);
        s2.add(new Month(2, 2011), 296.44);
        s2.add(new Month(3, 2011), 300.68);
        s2.add(new Month(4, 2011), 312.95);
        s2.add(new Month(5, 2011), 302.17);
        s2.add(new Month(6, 2011), 287.95);
        s2.add(new Month(7, 2011), 285.21);
        s2.add(new Month(8, 2011), 286.97);
        s2.add(new Month(9, 2011), 287.54);
        s2.add(new Month(10, 2011), 257.66);
        s2.add(new Month(11, 2011), 256.99);
        s2.add(new Month(12, 2011), 251.60);
        s2.add(new Month(1, 2012), 255.91);
        s2.add(new Month(2, 2012), 244.14);
        s2.add(new Month(3, 2012), 222.84);
        s2.add(new Month(4, 2012), 214.46);
        s2.add(new Month(5, 2012), 207.32);
        s2.add(new Month(6, 2012), 184.67);
        s2.add(new Month(7, 2012), 202.56);
        s2.add(new Month(8, 2012), 187.14);
        s2.add(new Month(9, 2012), 190.10);
        s2.add(new Month(10, 2012), 181.39);
        s2.add(new Month(11, 2012), 170.08);
        s2.add(new Month(12, 2012), 164.40);
        s2.add(new Month(1, 2013), 169.19);
        s2.add(new Month(2, 2013), 161.70);
        s2.add(new Month(3, 2013), 161.53);
        
        TimeSeries s3 = new TimeSeries("Other Milds");
        s3.add(new Month(1, 2010), 158.90);
        s3.add(new Month(2, 2010), 157.86);
        s3.add(new Month(3, 2010), 164.50);
        s3.add(new Month(4, 2010), 169.55);
        s3.add(new Month(5, 2010), 173.38);
        s3.add(new Month(6, 2010), 190.90);
        s3.add(new Month(7, 2010), 203.21);
        s3.add(new Month(8, 2010), 211.59);
        s3.add(new Month(9, 2010), 222.71);
        s3.add(new Month(10, 2010), 217.64);
        s3.add(new Month(11, 2010), 233.48);
        s3.add(new Month(12, 2010), 248.17);
        s3.add(new Month(1, 2011), 263.77);
        s3.add(new Month(2, 2011), 287.89);
        s3.add(new Month(3, 2011), 292.07);
        s3.add(new Month(4, 2011), 300.12);
        s3.add(new Month(5, 2011), 291.09);
        s3.add(new Month(6, 2011), 274.98);
        s3.add(new Month(7, 2011), 268.02);
        s3.add(new Month(8, 2011), 270.44);
        s3.add(new Month(9, 2011), 274.88);
        s3.add(new Month(10, 2011), 247.82);
        s3.add(new Month(11, 2011), 245.09);
        s3.add(new Month(12, 2011), 236.71);
        s3.add(new Month(1, 2012), 237.21);
        s3.add(new Month(2, 2012), 224.16);
        s3.add(new Month(3, 2012), 201.26);
        s3.add(new Month(4, 2012), 191.45);
        s3.add(new Month(5, 2012), 184.65);
        s3.add(new Month(6, 2012), 168.69);
        s3.add(new Month(7, 2012), 190.45);
        s3.add(new Month(8, 2012), 174.82);
        s3.add(new Month(9, 2012), 178.98);
        s3.add(new Month(10, 2012), 173.32);
        s3.add(new Month(11, 2012), 159.91);
        s3.add(new Month(12, 2012), 152.74);
        s3.add(new Month(1, 2013), 157.29);
        s3.add(new Month(2, 2013), 149.46);
        s3.add(new Month(3, 2013), 149.78);
        
        TimeSeries s4 = new TimeSeries("Brazilian Naturals");
        s4.add(new Month(1, 2010), 131.67);
        s4.add(new Month(2, 2010), 124.57);
        s4.add(new Month(3, 2010), 126.21);
        s4.add(new Month(4, 2010), 126.07);
        s4.add(new Month(5, 2010), 127.45);
        s4.add(new Month(6, 2010), 143.20);
        s4.add(new Month(7, 2010), 156.87);
        s4.add(new Month(8, 2010), 163.21);
        s4.add(new Month(9, 2010), 175.15);
        s4.add(new Month(10, 2010), 175.38);
        s4.add(new Month(11, 2010), 190.62);
        s4.add(new Month(12, 2010), 204.25);
        s4.add(new Month(1, 2011), 219.77);
        s4.add(new Month(2, 2011), 247.00);
        s4.add(new Month(3, 2011), 260.98);
        s4.add(new Month(4, 2011), 273.40);
        s4.add(new Month(5, 2011), 268.66);
        s4.add(new Month(6, 2011), 250.59);
        s4.add(new Month(7, 2011), 245.69);
        s4.add(new Month(8, 2011), 249.83);
        s4.add(new Month(9, 2011), 255.64);
        s4.add(new Month(10, 2011), 234.28);
        s4.add(new Month(11, 2011), 236.75);
        s4.add(new Month(12, 2011), 228.79);
        s4.add(new Month(1, 2012), 228.21);
        s4.add(new Month(2, 2012), 215.40);
        s4.add(new Month(3, 2012), 192.03);
        s4.add(new Month(4, 2012), 180.90);
        s4.add(new Month(5, 2012), 174.17);
        s4.add(new Month(6, 2012), 156.17);
        s4.add(new Month(7, 2012), 175.98);
        s4.add(new Month(8, 2012), 160.05);
        s4.add(new Month(9, 2012), 166.53);
        s4.add(new Month(10, 2012), 161.20);
        s4.add(new Month(11, 2012), 148.25);
        s4.add(new Month(12, 2012), 140.69);
        s4.add(new Month(1, 2013), 145.17);
        s4.add(new Month(2, 2013), 136.63);
        s4.add(new Month(3, 2013), 133.61);
        
        TimeSeries s5 = new TimeSeries("Robustas");
        s5.add(new Month(1, 2010), 69.92);
        s5.add(new Month(2, 2010), 67.88);
        s5.add(new Month(3, 2010), 67.25);
        s5.add(new Month(4, 2010), 71.59);
        s5.add(new Month(5, 2010), 70.70);
        s5.add(new Month(6, 2010), 76.92);
        s5.add(new Month(7, 2010), 85.27);
        s5.add(new Month(8, 2010), 82.68);
        s5.add(new Month(9, 2010), 81.28);
        s5.add(new Month(10, 2010), 85.27);
        s5.add(new Month(11, 2010), 92.04);
        s5.add(new Month(12, 2010), 94.09);
        s5.add(new Month(1, 2011), 101.09);
        s5.add(new Month(2, 2011), 109.35);
        s5.add(new Month(3, 2011), 118.13);
        s5.add(new Month(4, 2011), 117.37);
        s5.add(new Month(5, 2011), 121.98);
        s5.add(new Month(6, 2011), 117.95);
        s5.add(new Month(7, 2011), 112.73);
        s5.add(new Month(8, 2011), 112.07);
        s5.add(new Month(9, 2011), 106.06);
        s5.add(new Month(10, 2011), 98.10);
        s5.add(new Month(11, 2011), 97.24);
        s5.add(new Month(12, 2011), 98.41);
        s5.add(new Month(1, 2012), 96.72);
        s5.add(new Month(2, 2012), 101.93);
        s5.add(new Month(3, 2012), 103.57);
        s5.add(new Month(4, 2012), 101.80);
        s5.add(new Month(5, 2012), 106.88);
        s5.add(new Month(6, 2012), 105.70);
        s5.add(new Month(7, 2012), 107.06);
        s5.add(new Month(8, 2012), 106.52);
        s5.add(new Month(9, 2012), 104.95);
        s5.add(new Month(10, 2012), 104.47);
        s5.add(new Month(11, 2012), 97.67);
        s5.add(new Month(12, 2012), 96.59);
        s5.add(new Month(1, 2013), 99.69);
        s5.add(new Month(2, 2013), 104.03);
        s5.add(new Month(3, 2013), 106.26);
       
        TimeSeries s6 = new TimeSeries("Futures (London)");
        s6.add(new Month(1, 2010), 62.66);
        s6.add(new Month(2, 2010), 60.37);
        s6.add(new Month(3, 2010), 58.64);
        s6.add(new Month(4, 2010), 62.21);
        s6.add(new Month(5, 2010), 62.46);
        s6.add(new Month(6, 2010), 69.72);
        s6.add(new Month(7, 2010), 78.17);
        s6.add(new Month(8, 2010), 78.42);
        s6.add(new Month(9, 2010), 75.87);
        s6.add(new Month(10, 2010), 80.08);
        s6.add(new Month(11, 2010), 86.40);
        s6.add(new Month(12, 2010), 88.70);
        s6.add(new Month(1, 2011), 96.02);
        s6.add(new Month(2, 2011), 104.53);
        s6.add(new Month(3, 2011), 111.36);
        s6.add(new Month(4, 2011), 111.34);
        s6.add(new Month(5, 2011), 116.76);
        s6.add(new Month(6, 2011), 110.51);
        s6.add(new Month(7, 2011), 103.36);
        s6.add(new Month(8, 2011), 102.71);
        s6.add(new Month(9, 2011), 96.10);
        s6.add(new Month(10, 2011), 88.64);
        s6.add(new Month(11, 2011), 85.78);
        s6.add(new Month(12, 2011), 87.65);
        s6.add(new Month(1, 2012), 84.19);
        s6.add(new Month(2, 2012), 88.69);
        s6.add(new Month(3, 2012), 91.37);
        s6.add(new Month(4, 2012), 91.81);
        s6.add(new Month(5, 2012), 96.82);
        s6.add(new Month(6, 2012), 94.75);
        s6.add(new Month(7, 2012), 96.14);
        s6.add(new Month(8, 2012), 96.12);
        s6.add(new Month(9, 2012), 94.65);
        s6.add(new Month(10, 2012), 94.66);
        s6.add(new Month(11, 2012), 87.32);
        s6.add(new Month(12, 2012), 85.94);
        s6.add(new Month(1, 2013), 88.85);
        s6.add(new Month(2, 2013), 94.41);
        s6.add(new Month(3, 2013), 97.22);
        
        TimeSeries s7 = new TimeSeries("Futures (New York)");
        s7.add(new Month(1, 2010), 142.76);
        s7.add(new Month(2, 2010), 134.35);
        s7.add(new Month(3, 2010), 134.97);
        s7.add(new Month(4, 2010), 135.12);
        s7.add(new Month(5, 2010), 135.81);
        s7.add(new Month(6, 2010), 152.36);
        s7.add(new Month(7, 2010), 165.23);
        s7.add(new Month(8, 2010), 175.10);
        s7.add(new Month(9, 2010), 187.80);
        s7.add(new Month(10, 2010), 190.43);
        s7.add(new Month(11, 2010), 206.92);
        s7.add(new Month(12, 2010), 221.51);
        s7.add(new Month(1, 2011), 238.05);
        s7.add(new Month(2, 2011), 261.41);
        s7.add(new Month(3, 2011), 274.10);
        s7.add(new Month(4, 2011), 285.58);
        s7.add(new Month(5, 2011), 277.72);
        s7.add(new Month(6, 2011), 262.52);
        s7.add(new Month(7, 2011), 255.90);
        s7.add(new Month(8, 2011), 260.39);
        s7.add(new Month(9, 2011), 261.39);
        s7.add(new Month(10, 2011), 236.74);
        s7.add(new Month(11, 2011), 235.25);
        s7.add(new Month(12, 2011), 227.23);
        s7.add(new Month(1, 2012), 227.50);
        s7.add(new Month(2, 2012), 212.09);
        s7.add(new Month(3, 2012), 188.78);
        s7.add(new Month(4, 2012), 181.75);
        s7.add(new Month(5, 2012), 176.50);
        s7.add(new Month(6, 2012), 159.93);
        s7.add(new Month(7, 2012), 183.20);
        s7.add(new Month(8, 2012), 169.77);
        s7.add(new Month(9, 2012), 175.36);
        s7.add(new Month(10, 2012), 170.43);
        s7.add(new Month(11, 2012), 155.72);
        s7.add(new Month(12, 2012), 149.58);
        s7.add(new Month(1, 2013), 154.28);
        s7.add(new Month(2, 2013), 144.89);
        s7.add(new Month(3, 2013), 141.43);
       
        TimeSeriesCollection dataset = new TimeSeriesCollection();
        dataset.addSeries(s1);
        dataset.addSeries(s2);
        dataset.addSeries(s3);        
        dataset.addSeries(s4);
        dataset.addSeries(s5);
        dataset.addSeries(s6);
        dataset.addSeries(s7);
        return dataset;
    }

    public static void main(String[] args) throws FileNotFoundException, IOException {
        PdfWriter writer = new PdfWriter("ITextPDFWithChart.pdf");
        PdfDocument targetPDF = new PdfDocument(writer);
        Document document = new Document(targetPDF);
        document.add(new Paragraph("Demo showing a JFreeChart being rendered into a PDF document created by iText 7."));
        
        PdfReader reader = new PdfReader(new ByteArrayInputStream(generateChartPDF()));
        PdfDocument chartDoc = new PdfDocument(reader);
        PdfFormXObject chart = chartDoc.getFirstPage().copyAsFormXObject(targetPDF);
        Image chartImage = new Image(chart);
        document.add(new Paragraph("Here we add a chart... ").add(chartImage));
        document.close();
    }
    

}

The dependencies for compiling the above:

<dependencies>

    <dependency>
        <groupId>org.jfree</groupId>
        <artifactId>jfreechart</artifactId>
        <version>1.5.0</version>
    </dependency>
 
    <dependency>
        <groupId>com.orsonpdf</groupId>
        <artifactId>orsonpdf</artifactId>
        <version>1.7</version>
    </dependency>

    <dependency>
        <groupId>com.itextpdf</groupId>
        <artifactId>kernel</artifactId>
        <version>7.0.4</version>
    </dependency>
    
    <dependency>
        <groupId>com.itextpdf</groupId>
        <artifactId>io</artifactId>
        <version>7.0.4</version>
    </dependency>
    
    <dependency>
        <groupId>com.itextpdf</groupId>
        <artifactId>layout</artifactId>
        <version>7.0.4</version>
    </dependency>

</dependencies>

My blog doesn’t have a mechanism for commenting, but if you want to provide feedback then you can interact via Twitter: @david_m_gilbert.

JFreeChart Demo Programs

2017-11-20T00:00:00+00:00

Alongside JFreeChart and JFreeChart-FX, I have created a suite of demonstration applications to illustrate how to create various types of charts with these libraries.

To run these, you can download the following jar files:

You can run the JFreeChart demos using:

java -jar jfreechart-demo-1.5.0-jar-with-dependencies.jar

…and the JFreeChart FX demos using:

java -jar jfreechart-fx-demo-1.0-jar-with-dependencies.jar

The source code for these demos is made available when you support the JFreeChart Project. Please encourage your company to do so!

3D Charts for Java

2017-11-19T00:00:00+00:00

In the last week I continued my efforts to streamline my open source libraries, and released a new version of Orson Charts (a 3D chart library for the Java platform). I moved the JavaFX support into a separate project Orson Charts FX, transferred the demo code into separate projects and removed Ant build support (leaving just the Maven-based builds).

Here is a screenshot from the JavaFX demo application (which you can find in the JFree FX Demos project):

Also included in the release are a few bug fixes - here are the notes from the README.md file:

Version 1.7 : 17-Nov-2017

removed JavaFX support to a separate project Orson Charts FX;
fixed cell content bug in GridElement;
fixed bug in GradientColorScale;
protect from NullPointerException in AbstractValueAxis3D;
streamline build by removing Ant build support and moving demo code to external projects.

Run the Demo

Finally, if you are interested in running the demo code locally but don’t want to check out the demo project from GitHub, you can easily download the demo file and run it with:

java -jar jfree-demos-1.2-jar-with-dependencies.jar

Streamlining at JFree

2017-11-06T00:00:00+00:00

Yesterday I released new versions of JFreeChart (a 2D chart library for Java), JFreeChart-FX (JavaFX extensions for JFreeChart) and FXGraphics2D (a utility library that allows Java2D code to draw to a JavaFX Canvas). These are the first updates I’ve done in a long while. I have reduced time these days to devote to open source work, so I’ve put some focus into streamlining the build and release procedures that I’m using, with the aim that I will be able to do smaller and (hopefully) more frequent releases in the future.

So what exactly did I do to “streamline” the process? Read on…

The first step I have taken is to move the JavaFX code out of the JFreeChart project and into a new project JFreeChart-FX. This means I can have a standard “out-of-the-box” build mechanism for JFreeChart, and not have to provide instructions for “enabling” the JavaFX build which required a later version of the JDK (the non-JavaFX code in JFreeChart requires only JDK 1.6). Likewise, JFreeChart-FX has a standard build procedure, which simply specifies dependencies on JFreeChart and FXGraphics2D.

The second step was to drop Ant as a build option, to focus on Maven only. Over the years, I found Ant particularly useful for putting together ZIP file distributions of JFreeChart, including such things as dependencies as jar files, binary only demo files and other documentation. However, distributing new versions of JFreeChart in ZIP files doesn’t seem so useful anymore, and it certainly consumes my time to prepare and upload these archives to http://www.jfree.org/. I’m convinced that most developers these days are comfortable cloning a Git repo and building from source, or simply relying on downloading dependencies from a Maven repository using whatever build tool they prefer. If that’s not the case, at least the work is transferred to someone else!

A third step has been to merge the JCommon classes that JFreeChart uses, into JFreeChart itself. I’ve wanted to do this for a long time, since the dependency didn’t make a lot of sense as there wasn’t any other code relying on the “common” classes (well, a long time ago there was JFreeReport). Since I was restructuring the project for JavaFX, I decided to bump the version number on JFreeChart (to 1.5.0) and merge in the JCommon classes - this means that the core JFreeChart library is now a single jar file.

The last step was to move the (publicly available) demo classes into separate projects as well. I will maintain one demo project for JavaFX related code and another for non-JavaFX related code (typically Swing demos, but other standalone code such as the demos for JFreeSVG will end up in here). These projects are live already:

It is really my hope that these changes will lower the overheads for me when updating these projects, which should allow for more frequent releases.

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