Adding a Column to a JTable

Question

I have a simple gui where I query a database and return a result set in a JTable using a table model. I would like to be able to add a new column with checkboxes as the first column in the table. I've seen examples using checkboxes with boolen data from the database, but this column is not being returned from the database it is a new added column.
The first task is to add the column and I am struggling with this. My code is below.
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
public class DatabaseTest extends JFrame {
  private QueryTableModel qtm;
  public DatabaseTest()
    super("JTable Test");
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(350, 200);
    qtm = new QueryTableModel();
    JTable table = new JTable(qtm);
    JScrollPane scrollpane = new JScrollPane(table);
    JPanel p1 = new JPanel();
    p1.setLayout(new GridLayout(3, 2));
    p1.add(new JLabel("Click here to Query the DB: "));
    JButton jb = new JButton("Search");
    jb.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e)
        qtm.Query();
    p1.add(jb);
    getContentPane().add(p1, BorderLayout.NORTH);
    getContentPane().add(scrollpane, BorderLayout.CENTER);
  public static void main(String args[]) {
    DatabaseTest tt = new DatabaseTest();
    tt.setVisible(true);
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import java.util.Vector;
import javax.swing.table.AbstractTableModel;
class QueryTableModel extends AbstractTableModel {
  Vector cache;
  private int colCount;
  private String[] headers;
  Statement statement;
  private static Connection conn = null;
  public QueryTableModel() {
    cache = new Vector();
  public String getColumnName(int i) {
    return headers;
public int getColumnCount() {
return colCount;
public int getRowCount() {
return cache.size();
public Object getValueAt(int row, int col) {
return ((String[]) cache.elementAt(row))[col];
public void Query() {
cache = new Vector();
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:*****","******","*******");
statement = conn.createStatement();
ResultSet rs = statement.executeQuery("Select username from dba_users where rownum < 6");
ResultSetMetaData meta = rs.getMetaData();
colCount = meta.getColumnCount();
// Now we must rebuild the headers array with the new column names
headers = new String[colCount];
for (int h = 1; h <= colCount; h++) {
headers[h - 1] = meta.getColumnName(h);
while (rs.next()) {
String[] record = new String[colCount];
for (int i = 0; i < colCount; i++) {
record[i] = rs.getString(i + 1);
cache.addElement(record);
fireTableChanged(null);
// Add column code here?
} catch (Exception e) {
cache = new Vector(); // blank it out and keep going.
e.printStackTrace();
}Not sure how to add the column. I've tried a few variations of the following code with no luck:TableColumn tc = new TableColumn(0, 120);
tc.setHeaerValue("Name");
table.getColumnModel().addColumn(tc);Any help would be appreciated.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

The first task is to add the column Well, I like the suggestions from the link given in the above posting :-) It shows you how to dynamically alter the TableModel after its initial creation, and is probably the best generic solution.
But, just so you understand better how a TableModel works I"ll just put another thought in your mind. Maybe in this case you just create the TableModel correctly the first time so you don't need to do a dynamic change. The TableModel doesn't know where the data came from. It doesn't care that it came from a ResultSet. All it knows it that you have data in an array. So whats to prevent you from hard coding the first column to contain Boolean data?
{code}headers = new String[colCount+1];
headers[0] = "Boolean Column";
for (int h = 1; h <= colCount; h++)
headers[h] = meta.getColumnName(h);
while (rs.next())
String[] record = new String[colCount+1];
record[0] = new Boolean.FALSE;
for (int i = 1; i <= colCount; i++)
record[i] = rs.getString(i);
}{code}