Add rows and sort JTable in the same program

Question

I would like to have a button to add rows to the JTable, but would also like to sort the data within the columns. This program can sort the data prior to clicking the 'add row' button. After I click the button, there is no new row, and I lose the ability to sort the column. Do you have any tips or advice as to what I can do to fix my program? Is it because I have to have the final code for SortFilterModel to work?
Thanks
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
public class TableRowColumn extends JFrame
     private final static String LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
     JTable table;
     DefaultTableModel model;
     JPanel buttonPanel;
     JButton button;
     public TableRowColumn()
          Object[][] data = {
                    {"6", "K"},
                    {"5", "A"},
                    {"1", "Z"}
          String[] columnNames = {
                "Number",
                "Letter"
          model = new DefaultTableModel(data, columnNames);
                //comment out this SortFilterModel line
                final SortFilterModel sorter = new SortFilterModel(model);
                //Change sorter to model
          table = new JTable(sorter);
          table.putClientProperty("terminateEditOnFocusLost", Boolean.TRUE);
          //  Add table and a Button panel to the frame
          JScrollPane scrollPane = new JScrollPane( table );
          getContentPane().add( scrollPane );
          buttonPanel = new JPanel();
          getContentPane().add( buttonPanel, BorderLayout.SOUTH );
          button = new JButton( "Add Row" );
          buttonPanel.add( button );
          button.addActionListener( new ActionListener()
               public void actionPerformed(ActionEvent e)
                    model.addRow( createRow() );
                    int row = table.getRowCount() - 1;
                    table.changeSelection(row, row, false, false);
                    table.requestFocusInWindow();
             //Set up double click handler for column headers and sort
             table.getTableHeader().addMouseListener(new MouseAdapter(){
                    public void mouseClicked(MouseEvent event)
                      //check for click
                      if (event.getClickCount() < 2) return;
                   //find column of click and
                   int tableColumn = table.columnAtPoint(event.getPoint());
                   //translate to table model index and sort
                   int modelColumn = table.convertColumnIndexToModel(tableColumn);
                   sorter.sort(modelColumn);
     private Object[] createRow()
          Object[] newRow = new Object[2];
          int row = table.getRowCount() + 1;
          newRow[0] = Integer.toString( row );
          newRow[1] = LETTERS.substring(row-1, row);
          return newRow;
     public static void main(String[] args)
          TableRowColumn frame = new TableRowColumn();
          frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
          frame.pack();
          frame.setVisible(true);
}

Answer 1

I attempted to modify the code in the correct way, but I ran into a problem near the bottom with the model.addRow(rowData); line. It has an error saying it can't find the addRow method. If I take away the model part, it will compile, but it will cause an infinite loop when I push the 'Add Row' button within the program. I didn't expect that to work, and I think it isn't calling the right model.
I am aware that my code organization and design skills are not very good. I am a fan of basic assembly and low-level hardware languages for the most part.
Thanks for your advice so far, it has been helpful.
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
public class TableRowColumn extends JFrame
     private final static String LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
     JTable table;
     public DefaultTableModel model;
     JPanel buttonPanel;
     JButton button;
     public TableRowColumn()
          Object[][] data = {
                    {"9", "C"},
                    {"5", "A"},
                    {"3", "B"}
          String[] columnNames = {
                "Number",
                "Letter"
          model = new DefaultTableModel(data, columnNames);
                //comment out this SortFilterModel line
                final SortFilterModel sorter = new SortFilterModel(model);
                //Change sorter to model
          table = new JTable(sorter);
          table.putClientProperty("terminateEditOnFocusLost", Boolean.TRUE);
          //  Add table and a Button panel to the frame
          JScrollPane scrollPane = new JScrollPane( table );
          getContentPane().add( scrollPane );
          buttonPanel = new JPanel();
          getContentPane().add( buttonPanel, BorderLayout.SOUTH );
          button = new JButton( "Add Row" );
          buttonPanel.add( button );
          button.addActionListener( new ActionListener()
               public void actionPerformed(ActionEvent e)
                    sorter.addRow( createRow() );
                    int row = table.getRowCount() - 1;
                    table.changeSelection(row, row, false, false);
                    table.requestFocusInWindow();
             //Set up double click handler for column headers and sort
             table.getTableHeader().addMouseListener(new MouseAdapter(){
                    public void mouseClicked(MouseEvent event)
                      //check for click
                      if (event.getClickCount() < 2) return;
                   //find column of click and
                   int tableColumn = table.columnAtPoint(event.getPoint());
                   //translate to table model index and sort
                   int modelColumn = table.convertColumnIndexToModel(tableColumn);
                   sorter.sort(modelColumn);
     private Object[] createRow()
          Object[] newRow = new Object[2];
          int row = table.getRowCount() + 1;
          newRow[0] = Integer.toString( row );
          newRow[1] = LETTERS.substring(row-1, row);
          return newRow;
     public static void main(String[] args)
          TableRowColumn frame = new TableRowColumn();
          frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
          frame.pack();
          frame.setVisible(true);
class SortFilterModel extends AbstractTableModel{
    public SortFilterModel(TableModel m){
        model = m;
        rows = new Row[model.getRowCount()];
        for (int i = 0; i < rows.length; i++) {
            rows[i] = new Row();
            rows.index = i;
public void sort(int c){
sortColumn = c;
Arrays.sort(rows);
fireTableDataChanged();
public Object getValueAt(int r, int c) {
return model.getValueAt(rows[r].index, c);
public boolean isCellEditable(int r, int c){
return model.isCellEditable(rows[r].index, c);
public void setValueAt(Object aValue, int r, int c){
model.setValueAt(aValue, rows[r].index, c);
public int getRowCount() {
return model.getRowCount();
public int getColumnCount(){
return model.getColumnCount();
public String getColumnName(int c) {
return model.getColumnName(c);
public Class getColumnClass(int c){
return model.getColumnClass(c);
private class Row implements Comparable {
public int index;
public int compareTo(Object other) {
Row otherRow = (Row)other;
Object a = model.getValueAt(index, sortColumn);
Object b = model.getValueAt(otherRow.index, sortColumn);
if (a instanceof Comparable) {
return ((Comparable)a).compareTo(b);
else{
return a.toString().compareTo(b.toString());
public void addRow(Object[] rowData) {
Row[] oldRows = new Row[rows.length];
for (int i=0; i<rows.length; i++) {
oldRows[i] = rows[i];
rows = new Row[rows.length +1];
for (int i=0; i < oldRows.length; i++) {
rows[i] = oldRows[i];
rows[oldRows.length] = new Row();
rows[oldRows.length].index = oldRows.length;
addRow (rowData);
//model.addRow(rowData);
fireTableDataChanged();
private TableModel model;
private int sortColumn;
private Row[] rows;