JComboBox in JTree

Question

I have tried to implement the example from
http://www.mutualinstrument.com/Easy/easy.html
The method where I construct the body of the tree is here:
     public DefaultTreeModel createParticipantTree(Set participantSet) {
          javax.swing.tree.TreePath path = participantTree.getPathForRow(0);
          DefaultMutableTreeNode node =
               (DefaultMutableTreeNode) path.getLastPathComponent();
          DefaultTreeModel model = (DefaultTreeModel) participantTree.getModel();
          UserObject object = null;
          UserTreeNode child = null;
          JLabel textCellRenderer = new JLabel();
          TextCellEditor textCellEditor =
               new TextCellEditor(new javax.swing.JTextField());
          JComboBox comboBoxCellRenderer = null;
          ComboBoxCellEditor comboBoxCellEditor = null;
          PriceData priceData = null;
          VolumeData volumeData = null;
          Vector genVector = null;
          ItemListener listener = new ItemListener() {
               public void itemStateChanged(java.awt.event.ItemEvent e) {
                    JComboBox combo = (JComboBox) e.getSource();
                    if (e.getStateChange() == java.awt.event.ItemEvent.SELECTED) {
                         recreateCurve(combo.getName(), (String) e.getItem());
          for (Iterator iter = participantSet.iterator(); iter.hasNext();) {
               Participant participant = (Participant) iter.next();
               LegendItemCollection legendItems =
                    chart.getXYPlot().getLegendItems();
               String participantName = participant.getName();
               LegendItem legendItem = null;
               // Find appropriate legend item.
               for (int i = 0; i < legendItems.getItemCount(); i++) {
                    legendItem = legendItems.get(i);
                    if (participantName.equals(legendItem.getLabel())) {
                         break;
               UserObject partobject =
                    new UserText(
                         new JLabel(
                              new TreeIcon(legendItem.getPaint()),
                              SwingConstants.LEFT),
                         new TextCellEditor(new JTextField()),
                         participantName);
               UserTreeNode partchild = new UserTreeNode(partobject);
               DefaultMutableTreeNode partnode =
                    (DefaultMutableTreeNode) partchild;
               node.add(partchild);
               int[] newIndex = new int[1];
               newIndex[0] = node.getChildCount() - 1;
               model.nodesWereInserted(node, newIndex);
               List genList = participant.getGeneratorList();
               for (Iterator listIter = genList.iterator(); listIter.hasNext();) {
                    Generator generator = (Generator) listIter.next();
                    String duid = generator.getDuid();
                    object = new UserText(duid);
                    Vector dataVector = (Vector) generatorMap.get(duid);
                    genVector = new Vector();
                    if (dataVector != null) {
                         for (Iterator vectIter = dataVector.iterator();
                              vectIter.hasNext();
                              BidData bidData = (BidData) vectIter.next();
                              if (bidData instanceof PriceData) {
                              } else if (bidData instanceof VolumeData) {
                                   volumeData = (VolumeData) bidData;
                                   String bidText =
                                        volumeData.getBidType()
                                             + (volumeData.getRebidNumber() > 0
                                                       + String.valueOf(
                                                            volumeData.getRebidNumber())
                                   genVector.add(bidText);
                    } else {
                         continue;
                    child = new UserTreeNode(object);
                    partnode.add(child);
                    DefaultMutableTreeNode genNode = (DefaultMutableTreeNode)child;
                    int[] newIndex1 = new int[1];
                    newIndex1[0] = partnode.getChildCount() - 1;
                    model.nodesWereInserted(partnode, newIndex1);
                    if (genVector.size() > 0 && genNode != null) {
                         java.util.Collections.reverse(genVector);
                         Object[] objects = (Object[]) genVector.toArray();
                         String[] generators = new String[objects.length];
                         for (int n = 0; n < objects.length; n++) {
                              generators[n] = (String) objects[n];
                         comboBoxCellRenderer = new JComboBox();
                         comboBoxCellRenderer.setName(
                              (String) ((UserText) child.getUser()).getValue());
                         comboBoxCellRenderer.addItemListener(listener);
                         comboBoxCellEditor =
                              new ComboBoxCellEditor(comboBoxCellRenderer);
                         object =
                              new UserComboBox(
                                   comboBoxCellRenderer,
                                   comboBoxCellEditor,
                                   generators,
                                   generators[0]);
                         genNode = (DefaultMutableTreeNode)child;
                         child = new UserTreeNode(object);
                         genNode.add(child);
                         int[] newIndex2 = new int[1];
                         newIndex2[0] = genNode.getChildCount() - 1;
                         model.nodesWereInserted(genNode, newIndex2);
                    if (genNode.getChildCount() > 0 && genNode != null) {
                         partnode.add(genNode);
                         int[] newIndex3 = new int[1];
                         newIndex3[0] = partchild.getChildCount() - 1;
                         model.nodesWereInserted(partnode, newIndex3);
               if (partnode.getChildCount() == 0) {
                    node.remove(partnode);
                    int[] newIndex4 = new int[1];
                    newIndex4[0] = node.getChildCount() - 1;
                    model.nodesWereRemoved(
                         node,
                         newIndex4,
                         new Object[] { partchild });
          return null; //new DefaultTreeModel(top);
     }Basically the problem is that there is no problem selecting a combo box for the first time. However, on each subsequent occassion the combo box can only be selected if it is the only combobox visible in the tree.
If anyone can see any obvious problems, please advise.

Answer 1

Hi,
I've tried the new CellRenederer but I have to then create a custom CellEditor too implementing TreeCellEditor which I have done. However, I'm not sure its right:
class MyCellEditor implements TreeCellEditor {
public Component getTreeCellEditorComponent( JTree tree, Object value,
boolean selected, boolean expanded,
boolean leaf, int row ) {
if( value instanceof Component ) {
return (Component )value;
else {
return new JLabel( value.toString() );
public Object getCellEditorValue()
return (new JComboBox()); // I don't know what to return here.
public boolean isCellEditable(EventObject e) { return true; }
public boolean shouldSelectCell(EventObject e) {  return true; }
public boolean stopCellEditing() { return false; }
public void cancelCellEditing() {}
public void addCellEditorListener(CellEditorListener c) {}
public void removeCellEditorListener(CellEditorListener c) {}
Then when I run the code, I still just seem to be getting a textual version of the combo box. This time though, it doesn't update on double-clicking so it really must be the toString() representation.