Leaf and JTree

Question

Hi all,
I would like to ask a small question about JTree. Is there a way to not display leaf without removing them from the tree?
Actually I used a tricky whay by crating my own DefaultTreeCellRenderer and checking when it's the leaf I set the preferedSize to 0. However, by using this tricky way i have some weird behaviour with scrollPane.
Does anyone has an idea to not display leaf in a JTree?
Regards,
Raffael

Answer 1

Raffael wrote:
Hello,
thanks for your anserw. However, creating your own JTreeModel allow you to specify if a node is a leaf or not. But you will not being able to not draw it via the tree model or I m wrong?Your custom TreeModel will have to 'hide' the leaf nodes from objects that ask about them. Here's an example that wraps a DefaultTreeModel:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.WindowConstants;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;
public class HiddenLeaves {
    HiddenLeaves() {
        JFrame f= new JFrame();
        f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
        DefaultMutableTreeNode nodeA = new DefaultMutableTreeNode("Node A");
        nodeA.add(new DefaultMutableTreeNode("Leaf One"));
        nodeA.add(new DefaultMutableTreeNode("Leaf Two"));
        nodeA.add(new DefaultMutableTreeNode("Leaf Three"));
        DefaultMutableTreeNode nodeB = new DefaultMutableTreeNode("Node B");
        nodeB.add(new DefaultMutableTreeNode("Leaf Four"));
        nodeB.add(new DefaultMutableTreeNode("Leaf Five"));
        nodeB.add(new DefaultMutableTreeNode("Leaf Six"));
        root.add(nodeA);
        root.add(nodeB);
        final FilteredTreeModel model = new FilteredTreeModel(new DefaultTreeModel(root));
        final JTree tree = new JTree(model);
        f.add(new JScrollPane(tree), BorderLayout.CENTER);
        JButton b = new JButton("Toggle Leaf Display");
        b.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                boolean visible = model.isShowingLeaves();
                model.setShowingLeaves(!visible);
                tree.repaint();
        f.add(b, BorderLayout.SOUTH);
        f.setSize(400,300);
        f.setVisible(true);
    public static void main(String[] args) {
        new HiddenLeaves();
    private static class FilteredTreeModel implements TreeModel {
        private boolean showingLeaves = true;
        private DefaultTreeModel delegate;
        public FilteredTreeModel(DefaultTreeModel delegate) {
            this.delegate = delegate;
        public void setShowingLeaves(boolean show) {
            this.showingLeaves = show;
            delegate.reload();
        public boolean isShowingLeaves() {
            return showingLeaves;
        public Object getChild(Object parent, int index) {
            Object child = delegate.getChild(parent, index);
            if (!isShowingLeaves() && delegate.isLeaf(child)) {
                child = null;
            return child;
        public int getChildCount(Object parent) {
            int count = delegate.getChildCount(parent);
            if (!showingLeaves) {
                int newCount = count;
                for (int i = 0; i < count; i++) {
                    if (delegate.isLeaf(delegate.getChild(parent, i))) {
                        newCount--;
                count = newCount;
            return count;
        public int getIndexOfChild(Object parent, Object child) {
            int index = delegate.getIndexOfChild(parent, child);
            if (!showingLeaves) {
                if (delegate.isLeaf(child)) {
                    index = -1;
            return index;
        public Object getRoot() {
            return delegate.getRoot();
        public boolean isLeaf(Object node) {
            return delegate.isLeaf(node);
        public void valueForPathChanged(TreePath path, Object newValue) {
            delegate.valueForPathChanged(path, newValue);
        public void addTreeModelListener(TreeModelListener l) {
            delegate.addTreeModelListener(l);
        public void removeTreeModelListener(TreeModelListener l) {
            delegate.removeTreeModelListener(l);
}