Example: Table with a fixed row, feedback please

Question

I've done a lot of lurking and posted some questions on this forum, but I haven't contribued very much, so I thought I'd share the solution to a problem I recently had. The need I had was pretty straight forward: I have a row of reference data that I want to keep fixed at the top of a JTable while the user scrolls through any number of additional rows. The examples I've seen on the web, e.g,:
http://access1.sun.com/FAQSets/FixedRowExample.java.html
are either too complex or are overkill for the simple functionality I need.
My solution was to overload my table's HeaderRenderer so that they would contain my extra row of data, in addition to displaying normal header titles. I've provided the FixedRowHeaderRenderer class below, along with a main method to demonstrate the result. Any suggestions or feedback would be appreciated!
import javax.swing.*;
import javax.swing.table.*;
import java.awt.event.*;
import java.awt.*;
import java.util.*;
public class FixedRowHeaderRenderer extends DefaultTableCellRenderer {
  private Object[] headerData;
  private Font headerDataFont;
  private Color headerDataBackgroundColor, headerDataForegroundColor;
  public FixedRowHeaderRenderer(){
    this(null, null, null, null);
  public FixedRowHeaderRenderer(Object[] headerData, Font headerDataFont,
    Color headerDataForegroundColor, Color headerDataBackgroundColor){
    super();
    this.headerData = headerData;
    this.headerDataFont = headerDataFont;
    this.headerDataBackgroundColor = headerDataBackgroundColor;
    this.headerDataForegroundColor = headerDataForegroundColor;
  public Component getTableCellRendererComponent(JTable table, Object value,
                   boolean isSelected, boolean hasFocus, int row, int column) {
    JPanel panel = new JPanel(new BorderLayout());
    if (table != null) {
      JTableHeader header = table.getTableHeader();
      if (header != null) {
        setForeground(header.getForeground());
        setBackground(header.getBackground());
        setFont(header.getFont());
      if(headerData!=null) {
        DefaultTableCellRenderer headerCell = new DefaultTableCellRenderer();
        headerCell.setForeground(getHeaderDataForegroundColor());
        headerCell.setBackground(getHeaderDataBackgroundColor());
        headerCell.setFont(getHeaderDataFont());
        Object datum = headerData[column];
        headerCell.setText((datum == null || datum.toString().length()==0)?
          " " : datum.toString());
        headerCell.setBorder(UIManager.getBorder("TableHeader.cellBorder"));
        panel.add(headerCell, BorderLayout.SOUTH);
    setText((value == null) ? "" : value.toString());
    setBorder(UIManager.getBorder("TableHeader.cellBorder"));
    panel.add(this, BorderLayout.NORTH);
    return panel;
  public Object[] getHeaderData() {
    return headerData;
  public void setHeaderData(Object[] headerData) {
    this.headerData = headerData;
  public void setHeaderData(Vector headerData) {
    this.headerData = headerData.toArray();
  public Font getHeaderDataFont() {
    if(headerDataFont == null) {
      return getFont();
    return headerDataFont;
  public Color getHeaderDataBackgroundColor() {
    if(headerDataBackgroundColor == null) {
      return getBackground();
    return headerDataBackgroundColor;
  public Color getHeaderDataForegroundColor() {
    if(headerDataForegroundColor == null) {
      return getForeground();
    return headerDataForegroundColor;
  public void setHeaderDataFont(Font font) {
    headerDataFont = font;
  public void setHeaderDataBackgroundColor(Color color) {
    headerDataBackgroundColor = color;
  public void setHeaderDataForegroundColor(Color color) {
    headerDataForegroundColor = color;
  public static void main(String[] args) {
    class FixedRowTableDemo extends JFrame {
      FixedRowTableDemo() {
        this.addWindowListener(new WindowAdapter() {
          public void windowClosing(WindowEvent e) {
            System.exit(0);
        setSize(Toolkit.getDefaultToolkit().getScreenSize().width/4,
          Toolkit.getDefaultToolkit().getScreenSize().height/4);
        String a = "a", b = "b", c = "c";
        int rowcount = 0;
        Object[][] data = new Object[][]{{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c},
        {new Integer(rowcount++),a,b,c},{new Integer(rowcount++),a,b,c}};
        Object[] headers = new Object[]{"rowcount",a,b,c};
        Object[] headerData = new Object[]{"",c,b,a};
        JTable table = new JTable(data, headers);
        table.getTableHeader().setDefaultRenderer(new FixedRowHeaderRenderer(null,
          new Font(table.getFont().getName(), Font.ITALIC, table.getFont().getSize()),
          Color.yellow, Color.red));
        JScrollPane scroll = new JScrollPane(table);
        this.getContentPane().add(scroll);
        this.show();
        ((FixedRowHeaderRenderer)table.getTableHeader().getDefaultRenderer()).
          setHeaderData(headerData);
    FixedRowTableDemo demo = new FixedRowTableDemo();
}

Answer 1

nice! really, really nice!