JTree sizing question...

Question

Hello:
I have a JTree for which each cell contains a button. I have written a renderer that renders the button, and I realize that I have to do some special stuff to capture a click on the button. My question is unrelated to all of that.
The problem is that over time, the labels on my buttons change (and may become longer (wider)), but the tree size does not change. In fact, when I update the button label and the tree is re-rendered the rendering of the button gets "chopped off". I've put the tree in a scroll pane, but this doesn't help - the right side of some of the buttons get cut off to the original tree size. I've tried lots of different variations on setPreferredSize, calling repaint, etc, and am not having any luck. I've put together a demonstration of this behavior in a smallish application that I'm posting here, where I create a 2 node tree with buttons that read "Hi", then I change the button labels to "Goodbye" and re-render. You'll see that the button's are cut off about halfway through the button.
In case its important - I'm running java version 1.5.0_07 on a 32-bit Linux box.
Any help would be greatly appreciated. Thanks in advance!
import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
public class JTreeQuestion
  public static void main(String [] args)
    JTreeFrame f = new JTreeFrame();
    f.pack();
    f.setLocation(30, 30);
    //Draws buttons with "Hi" (short string)
    f.setVisible(true);
    ButtonNode.updateString("Goodbye");
    //Draws buttons with longer string, buttons get "cut off"
    f.repaint();
class JTreeFrame extends JFrame
  JTree tree;
  JScrollPane treeView;
  public JTreeFrame()
    super("My Tree");
    DefaultMutableTreeNode root;
    root = new DefaultMutableTreeNode(new ButtonNode());
    root.add(new DefaultMutableTreeNode(new ButtonNode()));
    tree = new JTree(root);
    tree.setCellRenderer(new ButtonNodeRenderer());
    treeView = new JScrollPane(tree);
    add(treeView);
class ButtonNode
  public static String str = "Hi";
  public static void updateString(String inStr)
  { str = inStr; }
  String getStr()
  { return str; }
class ButtonNodeRenderer extends DefaultTreeCellRenderer
  public Component getTreeCellRendererComponent(JTree tree,
                          Object value, boolean sel, boolean expanded,
                          boolean leaf, int row, boolean hasFocus)
    Box theBox = new Box(BoxLayout.X_AXIS);
    super.getTreeCellRendererComponent(tree, value, sel, expanded,
                                       leaf, row, hasFocus);
    DefaultMutableTreeNode jtreeNode = (DefaultMutableTreeNode)value;
    theBox.add(new JButton(((ButtonNode)jtreeNode.getUserObject()).getStr()));
    return (theBox);
}

Answer 1

For those who are interested. The DefaultTreeModel has a method named nodeChanged() that tells the tree model that a specific node has changed, and the model re-interprets the cell causing its sizse to change as necessary, so that the full button is rendered now.
Basically what I did was instead of calling repain, I call a method that I wrote that loops through all the tree nodes, indicates they have changed, then repaint's, and it all works out. My trees are relatively small, so this is fine, but if others face the same problem, you'll probably want to selectively indicate which nodes have changed so the tree model doesn't have to do more work than necessary.