Programmatically selecting a cell in a two-dimensional JTable

Question

The problem is that when a person edits a cell and the value fails validation, I would like to programmatically select the cell. The validation is done in the setValueAt method of a Class extending the AbstractTableModel. By simply returning out of that method, the cell value is set back to the way it was before the user changed it. In addition, I would like the problem cell to be automatically selected rather than requiring the user to click in it to select it. The first question is 1- Is this possible, and 2- Any clues as to how to select it?
We find for examle in Chapter 6 of the CoreJava 2 Vol II Advanced features statements like this on page 399 of, I think, Edition 4, (can anyone tell what edition it is?) by Cay Horstmann
void setCellSelectionEnabled(boolean b)
If b is true, then individual cells are selected (when the user clicks in the cell?). I have researched this problem for several days and don't have a clue how to automatically select the cell although I know precisely what row and column it is.

Answer 1

This is the code to return the focus to error cell.
/* TableCellValidator class */
/* The class basically validates the input entry in a cell and */
/* pops up a JOptionPane if its an invalid input */
/* And an OK is clicked on the JOptionPane, the control returns back */
/* to the same cell */
/* Basic Idea: The controls Arrow/Tab/mouse clicks are handled by our */
/* ----------- custom table. Its has been slightly tricky to handle */
/* mouse clicks, since when you click the next cell, the */
/* editingrow/editingcol advances. Hence the */
/* previousrow/previouscol has been captured in the */
/* setValueAt method. */
/* To capture Table/Arrow/Numeric Arrow, The keyStrokes(TAB etc)*/
/* assigned different AbstractionActions to execute like */
/* validateBeforeTabbingToNextCell */
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
public class TableCellValidator {
* Constructor.
* Basically instantiates the class and sets up the
* JFrame object and the table.
public TableCellValidator() {
JFrame f = new JFrame("JTable test");
f.getContentPane().add(new JScrollPane(createTable()), "Center");
f.pack();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
* A method which created our custom table.
* The JTable methods processMouseEvent
* and setValueAt are overridden to handle
* Mouseclicks.
* The Tables ActionMap is fed with different
* AbstractAction classes eg: (validateBeforeTabbingToNextCell)
* (Scroll down below for the innerclass
* validateBeforeTabbingToNextCell).
* So basically when TAB is pressed the stuff present
* in the validateBeforeTabbingToNextCell's actionPerformed(..)
* method is performed.
* So we need to handle all the stuff a TAB does.
* ie. if a TAB hits the end of the row, we need to increment
* it to the next Row (if the validation is successful)
* in the current row etc..
* @return JTable
* @see validateBeforeTabbingToNextCell
* @see validateBeforeShiftTabbingToNextCell
* @see validateBeforeMovingToNextCell
* @see validateBeforeMovingDownToCell
* @see validateBeforeMovingUpToCell
* @see validateBeforeMovingLeftToCell
private JTable createTable() {
JTable table = new JTable(createModel()){
private int previousRow =0;
private int previousCol =0;
* Processes mouse events occurring on this component by
* dispatching them to any registered
* <code>MouseListener</code> objects.
* <p>
* This method is not called unless mouse events are
* enabled for this component. Mouse events are enabled
* when one of the following occurs:
* <p><ul>
* <li>A <code>MouseListener</code> object is registered
* via <code>addMouseListener</code>.
* </ul>
* <p>Note that if the event parameter is <code>null</code>
* the behavior is unspecified and may result in an
* exception.
* @param e the mouse event
* @see java.awt.event.MouseEvent
* @see java.awt.event.MouseListener
* @see #addMouseListener
* @see #enableEvents
* @since JDK1.1
protected void processMouseEvent(MouseEvent e) {
boolean canMoveFocus = true;
int currentRowAndColumn[] = getCurrentRowAndColumn(this); //we pull the current row and column
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
if ( e.getID() == MouseEvent.MOUSE_PRESSED || e.getID() == MouseEvent.MOUSE_CLICKED) {
stopCurrentCellBeingEdited(this); //stop the cellbeing edited to grab its value
final String value = (String)getModel().getValueAt(row,column);
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
JOptionPane.showMessageDialog(null,"Alpha value ="+ value ,"Invalid entry!",JOptionPane.WARNING_MESSAGE);
changeSelection(previousRow,previousCol, true, true);
editCellAt(previousRow, previousCol);
requestFocus(); // or t.getEditorCompo
if ( canMoveFocus ) {
super.processMouseEvent(e);
* The method setValueAt of the JTable is overridden
* to save the previousRow/previousCol to enable us to
* get back to the error cell when a Mouse is clicked.
* This is circumvent the problem, when a mouse is clicked in
* a different cell, the control goes to that cell and
* when you ask for getEditingRow , it returns the row that
* the current mouse click occurred. But we need a way
* to stop at the previous cell(ie. the cell that we were editing
* before the mouse click occurred) when an invalid data has
* been entered and return the focus to that cell
* @param aValue
* @param row
* @param col
public void setValueAt(Object aValue,int row, int col) {     
this.previousRow = row;
this.previousCol = col;
super.setValueAt(aValue,row,col);
/* These are the various KeyStrokes like
ENTER,SHIFT-TAB,TAB,Arrow Keys,Numeric Arrow keys being assigned an Abstract action (key string ) in to the
inputMap first . Then an Action is assigned in the ActionMap object
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_TAB,0) ,"validateBeforeTabbingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_TAB,1) ,"validateBeforeShiftTabbingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT,0) ,"validateBeforeMovingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_RIGHT,0) ,"validateBeforeMovingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN,0) ,"validateBeforeMovingDownToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_DOWN,0) ,"validateBeforeMovingDownToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER,0) ,"validateBeforeMovingDownToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP,0) ,"validateBeforeMovingUpToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_UP,0) ,"validateBeforeMovingUpToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT,0) ,"validateBeforeMovingLeftToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_LEFT,0) ,"validateBeforeMovingLeftToCell");
table.getActionMap().put("validateBeforeTabbingToNextCell",
new validateBeforeTabbingToNextCell());
table.getActionMap().put("validateBeforeShiftTabbingToNextCell",
new validateBeforeShiftTabbingToNextCell());
table.getActionMap().put("validateBeforeMovingToNextCell",
new validateBeforeMovingToNextCell());
table.getActionMap().put("validateBeforeMovingDownToCell",
new validateBeforeMovingDownToCell());
table.getActionMap().put("validateBeforeMovingUpToCell",
new validateBeforeMovingUpToCell());
table.getActionMap().put("validateBeforeMovingLeftToCell",
new validateBeforeMovingLeftToCell());
table.setPreferredScrollableViewportSize(table.getPreferredSize());
return table;
* A table model is created here for 5 rows/5 columns.
* And the isCellEditable is overridden to return true,
* indicating that the cell can be edited.
* So fine tuned control can be done here by saying,
* the user can be allowed to edit Row 1,3 or 5 only.
* or column 1 only etc..
* @return DefaultTableModel
private DefaultTableModel createModel() {
DefaultTableModel model = new DefaultTableModel(5, 5) {
public boolean isCellEditable(int row, int column) {
return true;
return model;
* This method basically returns the currentRow/currentCol value
* If the current Row/Col is being edited then
* it returns the getEditingRow/getEditingColumn
* If its not being edited,
* it return the getAnchorSelectionIndex of the JTables
* ListSelectionModel.
* If the column or row is -1, then it return 0.
* The first element in the int[] array is the row
* The second element in the int[] array is the column
* @param t input a JTable
* @return int[]
* @see ListSelectionModel
* @see JTable
private int[] getCurrentRowAndColumn(JTable t){
int[] currentRowAndColum = new int[2];
int row, column;
if (t.isEditing()) {
row = t.getEditingRow();
column = t.getEditingColumn();
} else {
row = t.getSelectionModel().getAnchorSelectionIndex();
if (row == -1) {
if (t.getRowCount() == 0) {
//actually this should never happen.. we need to return an exception
return null;
column =t.getColumnModel().getSelectionModel().getAnchorSelectionIndex();
if (column == -1) {
if (t.getColumnCount() == 0) {
//actually this should never happen.. we need to return an exception
return null;
column = 0;
currentRowAndColum[0]=row;
currentRowAndColum[1]=column;
return currentRowAndColum;
* Tbis basically a wrapper method for CellEditors,
* stopCellEditing method.
* We need to do this because,
* for instance we have entered a value in Cell[0,0] as 3
* and when we press TAB or mouse click or any other relevant
* navigation keys,
* ** IF the cell is BEING EDITED,
* when we do a getValueAt(cellrow,cellcol) at the TableModel
* level , it would return "null". To overcome this problem,
* we tell the cellEditor to stop what its doing. and then
* when you do a getValueAt[cellrow,cellcol] it would
* return us the current cells value
* @param t Input a JTable
* @see CellEditor
private void stopCurrentCellBeingEdited(JTable t){
CellEditor ce = t.getCellEditor(); /*this not the ideal way to do..
since there is no way the CellEditor could be null.
But a nullpointer arises when trying to work with mouse.. rather than just
keyboard" */
if (ce!=null) {
ce.stopCellEditing();
* The following Action class handles when a
* RIGHT ARROW or NUMERIC RIGHT ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move it to the
* next Cell.. else take it back to the currentCell
class validateBeforeMovingToNextCell extends AbstractAction {
* The following Action class handles when a
* DOWN ARROW or NUMERIC DOWN ARROW is pressed.
* There is just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move it to
* down by one Cell.. else take it back to the currentCell
* @param e
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column++;
if (column >= t.getColumnCount())
column = column-1;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a
* DOWN ARROW or NUMERIC DOWN ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move it to the
* down by Cell.. else take it back to the currentCell
class validateBeforeMovingDownToCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
row++;
if (row >= t.getRowCount())
row = row - 1;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a
* UP ARROW or NUMERIC UP ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeMovingUpToCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
row--;
if (row <0)
row = 0;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a
* LEFT ARROW or NUMERIC LEFT ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeMovingLeftToCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column--;
if (column <0)
column = 0;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a TAB is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeTabbingToNextCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column++;
int rows = t.getRowCount(), columns = t.getColumnCount();
while (row < rows) {
while (column < columns) {
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
column++;
row++;
column = 0;
row = 0;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a SHIFT TAB is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeShiftTabbingToNextCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column--;
int rows = t.getRowCount(), columns = t.getColumnCount();
while ((row < rows) && (row >= 0)) {
while ((column < columns) && (column >= 0)) {
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
column--;
row--;
column = columns - 1;
row = rows - 1;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
public static void main(String[] args) {
new TableCellValidator();