Struggling with Swingx Tr

"Rogan Dawes" <rogan.dawes@THRWHITE.remove-dii-this>
Wed, 27 Apr 2011 15:41:36 GMT
Hi folks,

I am struggling to figure out what I am doing wrong in this TreeModel
implementation. It seems like certain nodes are not being rendered, even
though I can see that the (custom) renderer *is* actually being called
for all the rows. Which is just weird!

I am trying to show a JSON Object hierarchy in a JTree (actually a
SwingX JXTreeTable, which is where this first manifested).

The example shows a broken example, and a working example (if you
uncomment the code in main() at the bottom). As can be seen from the
println statements in the TreeCellRenderer, it *is* being called for
each row, but the row is not actually being rendered at all.

The obvious difference between the two examples is that the non-rendered
nodes now have a child, but I'd hope that that shouldn't make any real

Any ideas?


===== Snip =====

package jtreetable;

import java.awt.BorderLayout;
import java.awt.Component;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;

public class TreeTableDemo extends JFrame {

     public TreeTableDemo(String title, Object data) {
         super("TreeTableDemo - " + title);
         JsonTreeModel model = new JsonTreeModel(data);
         JTree tree = new JTree(model);
         tree.setCellRenderer(new JsonTreeTableCellRenderer());
         getRootPane().setLayout(new BorderLayout());
         getRootPane().add(new JScrollPane(tree), BorderLayout.CENTER);
         setSize(300, 200);

     private class JsonTreeModel implements TreeModel {

         private Object json;

         public JsonTreeModel(Object json) {
             this.json = json;

         // Empty, since the tree is static in this example
         public void addTreeModelListener(TreeModelListener l) {}

         public boolean isLeaf(Object node) {
             return false;

         // Empty, since the tree is static in this example
         public void removeTreeModelListener(TreeModelListener l) {}

         // Empty, since the tree is static in this example
         public void valueForPathChanged(TreePath path, Object newValue) {}

         public Object getRoot() {
             return json;

         public Object getChild(Object parent, int index) {
             if (parent instanceof Map) {
                 Map map = (Map) parent;
                 Iterator it = map.keySet().iterator();
                 for (int i=0; i<index; i++);
                 return map.get(;
             } else if (parent instanceof Collection) {
                 Iterator it = ((Collection) parent).iterator();
                 for (int i=0; i<index; i++);
             throw new IndexOutOfBoundsException("'" + parent + "'
cannot have children!");

         public int getChildCount(Object parent) {
             int count = 0;
             if (parent instanceof Map) {
                 count = ((Map) parent).size();
             } else if (parent instanceof Collection) {
                 count = ((Collection) parent).size();
             return count;

         public int getIndexOfChild(Object parent, Object child) {
             if (parent instanceof Map) {
                 Iterator it = ((Map) parent).entrySet().iterator();
                 for (int i=0; it.hasNext(); i++)
                     if ( == child)
                         return i;
             } else if (parent instanceof Collection) {
                 Iterator it = ((Collection) parent).iterator();
                 for (int i=0; it.hasNext(); i++)
                     if ( == child)
                         return i;
             throw new IndexOutOfBoundsException("'" + parent + "'
cannot have children!");


     public class JsonTreeTableCellRenderer extends
DefaultTreeCellRenderer {
         public JsonTreeTableCellRenderer() {

         public Component getTreeCellRendererComponent(JTree tree,
Object node,
                 boolean sel, boolean expanded, boolean leaf, int row,
                 boolean hasFocus) {
             node = row + ": '" + node.toString() + "'";
             super.getTreeCellRendererComponent(tree, node, sel, expanded,
                     leaf, row, hasFocus);
             return this;

     public static void main(String[] args) {
         ArrayList data = new ArrayList();
         for (int i=0; i< 3; i++) {
             data.add(new HashMap());

         final TreeTableDemo broken = new TreeTableDemo("broken", data);
         SwingUtilities.invokeLater(new Runnable() {
             public void run() {

         data = new ArrayList();
         for (int i=0; i< 3 ; i++) {
             HashMap map = new HashMap();
             map.put("" + i, "Value " + i);

// final TreeTableDemo works = new TreeTableDemo("works", data);
// SwingUtilities.invokeLater(new Runnable() {
// public void run() {
// works.setVisible(true);
// }
// });


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