How to hide a tree node from the GUI but still keep it in the tree model?

Question

Hi, All
I used a JTree in my project in which I have a DefaultTreeModel to store all the tree structure and a JTree show it on the screen. But for some reason, I want to hide some of the nodes from the user, but I don't want to remove them from the tree model because later on I still need to use them.
I searched on the web, some people suggested method to hide the root node, but that's not appliable to my project because I want to hide some non-root nodes; Some people also suggested to collapse the parent node when there are child to hide, it is not appliable to me either, because there still some other childnodes (sibling of the node to hide) I want to show.
How can I hide some of the tree node from the user? Thanks for any information.
Linda

Answer 1

Here's an example using a derivation of DefaultTreeModel that shows (or does not show) two types of Sneech (appologies to the good Dr Zeus) by overiding two methods on the model.
Now, there are many things wrong with this example (using instanceof, for example), but it's pretty tight and shows one way of doing what you want.
Note: to make it useful, you''d have to change the implementation of setShowStarBelliedSneeches() to do something more sophisticated than simply firing a structure change event on the root node. You'd want to find all the star bellied sneech nodes and call fireTreeNodesRemoved(). That way the tree would stay expanded rather than collapse as it does now.
import javax.swing.JTree;
import javax.swing.JScrollPane;
import javax.swing.JOptionPane;
import javax.swing.JCheckBox;
import javax.swing.JPanel;
import javax.swing.tree.TreePath;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.DefaultMutableTreeNode;
import java.awt.Dimension;
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Enumeration;
class FilteredTree
     private class PlainBelliedSneech {
          public String toString() { return "Plain Bellied Sneech"; }
     private class StarBelliedSneech {
          public String toString() { return "Star Bellied Sneech"; }
     private class FilteredTreeModel
          extends DefaultTreeModel
          private boolean mShowStarBelliedSneeches= true;
          private DefaultMutableTreeNode mRoot;
          FilteredTreeModel(DefaultMutableTreeNode root)
               super(root);
               mRoot= root;
          public Object getChild(Object parent, int index)
               DefaultMutableTreeNode node=
                    (DefaultMutableTreeNode) parent;
               if (mShowStarBelliedSneeches)
                    return node.getChildAt(index);
               int pos= 0;
               for (int i= 0, cnt= 0; i< node.getChildCount(); i++) {
                    if (((DefaultMutableTreeNode) node.getChildAt(i)).getUserObject()
                                        instanceof PlainBelliedSneech)
                         if (cnt++ == index) {
                              pos= i;
                              break;
               return node.getChildAt(pos);
          public int getChildCount(Object parent)
               DefaultMutableTreeNode node=
                    (DefaultMutableTreeNode) parent;
               if (mShowStarBelliedSneeches)
                    return node.getChildCount();
               int childCount= 0;
               Enumeration children= node.children();
               while (children.hasMoreElements()) {
                    if (((DefaultMutableTreeNode) children.nextElement()).getUserObject()
                                        instanceof PlainBelliedSneech)
                         childCount++;
               return childCount;
          public boolean getShowStarBelliedSneeches() {
               return mShowStarBelliedSneeches;
          public void setShowStarBelliedSneeches(boolean showStarBelliedSneeches)
               if (showStarBelliedSneeches != mShowStarBelliedSneeches) {
                    mShowStarBelliedSneeches= showStarBelliedSneeches;
                    Object[] path= { mRoot };
                    int[] childIndices= new int[root.getChildCount()];
                    Object[] children= new Object[root.getChildCount()];
                    for (int i= 0; i< root.getChildCount(); i++) {
                         childIndices= i;
                         children[i]= root.getChildAt(i);
                    fireTreeStructureChanged(this, path, childIndices, children);
     private FilteredTree()
          final DefaultMutableTreeNode root= new DefaultMutableTreeNode("Root");
          DefaultMutableTreeNode parent;
          DefaultMutableTreeNode child;
          for (int i= 0; i< 2; i++) {
               parent= new DefaultMutableTreeNode(new PlainBelliedSneech());
               root.add(parent);
               for (int j= 0; j< 2; j++) {
                    child= new DefaultMutableTreeNode(new StarBelliedSneech());
                    parent.add(child);
                    for (int k= 0; k< 2; k++)
                         child.add(new DefaultMutableTreeNode(new PlainBelliedSneech()));
               for (int j= 0; j< 2; j++)
                    parent.add(new DefaultMutableTreeNode(new PlainBelliedSneech()));
               parent= new DefaultMutableTreeNode(new StarBelliedSneech());
               root.add(parent);
               for (int j= 0; j< 2; j++) {
                    child= new DefaultMutableTreeNode(new PlainBelliedSneech());
                    parent.add(child);
                    for (int k= 0; k< 2; k++)
                         child.add(new DefaultMutableTreeNode(new StarBelliedSneech()));
               for (int j= 0; j< 2; j++)
                    parent.add(new DefaultMutableTreeNode(new StarBelliedSneech()));
          final FilteredTreeModel model= new FilteredTreeModel(root);
          JTree tree= new JTree(model);
tree.setShowsRootHandles(true);
tree.putClientProperty("JTree.lineStyle", "Angled");
          tree.setRootVisible(false);
          JScrollPane sp= new JScrollPane(tree);
          sp.setPreferredSize(new Dimension(200,400));
          final JCheckBox check= new JCheckBox("Show Star Bellied Sneeches");
          check.setSelected(model.getShowStarBelliedSneeches());
          check.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent e) {
                    model.setShowStarBelliedSneeches(check.isSelected());
          JPanel panel= new JPanel(new BorderLayout());
          panel.add(check, BorderLayout.NORTH);
          panel.add(sp, BorderLayout.CENTER);
          JOptionPane.showOptionDialog(
               null, panel, "Sneeches on Beeches",
               JOptionPane.DEFAULT_OPTION,
               JOptionPane.PLAIN_MESSAGE,
               null, new String[0], null
          System.exit(0);
     public static void main(String[] argv) {
          new FilteredTree();