Customized JComboBox Editor for JTable

Question

Hi,
I am new to swing development and have gotten my self stuck on an issue. Basically I have a JTable that is dynamically populated from the database, in which one of the columns has a customized JComboBox Renderer and Editor. The default values load up fine when the page loads up but when I selected a new value in the combo box and select a new row in the JTable, the combo box defaults back to the original value. How can I make sure that the new selection is maintain.
Thanks, Anthony
Here are my Driver, Renderer and Editor:
excerpts from the Driver
contract.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
keys = contractSelectedEvent.getKeys();
String sql = contractSelectedEvent.getSchdSql(keys);
table = contractSelectedEvent.getStatusTable(sql);
table.setDefaultRenderer(CashFlow.class, new CashFlowRenderer());
table.setDefaultEditor(CashFlow.class, new CashFlowEditor());
public class CashFlowRenderer extends JComboBox implements TableCellRenderer {
protected QueryComboBoxModel comboModel;
/** Creates a new instance of CashFlowRenderer */
public CashFlowRenderer() {
super();
comboModel = new QueryComboBoxModel("Select Ref_ID, Ref_Desc From Ref Where
Ref_Typ_ID = 910 order by Ref_ID ");
super.setModel(comboModel);
public java.awt.Component getTableCellRendererComponent(javax.swing.JTable table,
Object value,
boolean isSelected,
boolean hasFocus,
int row,
int column) {
if(value == null) {
return this;
if(value instanceof CashFlow) {
//set the cashflow equal to the value
CashFlow cashFlow = new CashFlow(((CashFlow) value).getCashFlow());
setSelectedItem(cashFlow);
else {
//default the cashflow
CashFlow cashFlow = new CashFlow();
setSelectedItem(cashFlow.getCashFlow());
return this;
public boolean isCellEditable() {
return true;
public class CashFlowEditor extends JComboBox implements TableCellEditor {
protected transient Vector listeners;
protected transient String originalValue;
protected QueryComboBoxModel comboModel;
/** Creates new CashFlowEditor */
public CashFlowEditor() {
super();
comboModel = new QueryComboBoxModel("Select Ref_ID, Ref_Desc From Ref Where Ref_Typ_ID = 910 order by Ref_ID ");
super.setModel(comboModel);
listeners = new Vector();
public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
if(value == null) {
return this;
if (value instanceof CashFlow) {
setSelectedItem(((CashFlow)value).getCashFlow());
else {
CashFlow cashFlow = new CashFlow();
setSelectedItem(cashFlow.getCashFlow());
table.setRowSelectionInterval(row, row);
table.setColumnSelectionInterval(column, column);
originalValue = (String) getSelectedItem();
return this;
public void cancelCellEditing() {
fireEditingCanceled();
public Object getCellEditorValue() {
return (String)getSelectedItem();
public boolean isCellEditable(EventObject eo) {
return true;
public boolean shouldSelectCell(EventObject eo) {
return true;
public boolean stopCellEditing() {
CashFlow cashflow = new CashFlow((String)getSelectedItem());
setSelectedItem(cashflow.getCashFlow());
fireEditingStopped();
return true;
public void addCellEditorListener(CellEditorListener cel) {
listeners.addElement(cel);
public void removeCellEditorListener(CellEditorListener cel) {
listeners.removeElement(cel);
protected void fireEditingCanceled() {
setSelectedItem(originalValue);
ChangeEvent ce = new ChangeEvent(this);
for(int i = listeners.size(); i >= 0; i--) {
((CellEditorListener)listeners.elementAt(i)).editingCanceled(ce);
protected void fireEditingStopped() {
ChangeEvent ce = new ChangeEvent(this);
for(int i = listeners.size() - 1; i >= 0; i--) {
((CellEditorListener)listeners.elementAt(i)).editingStopped(ce);

Answer 1

First off, I wouldn't subclass JComboBox to create a custom renderer/editor. I would have a renderer/editor component that makes use of a JComboBox. But that is just me.
In order for setSelectedItem to work, the items in your combo box have to compare against each other correctly with equals(). Since you are creating new instances, your objects (even though they contain the same data) are going to be different instances and aren't going to be considered equal. Write your own equals() method in your CashFlow object that tests for equality based on the actual values in the objects and you should be fine.