Jtree Select node and change leafs icon problem

Question

Hi All,
i create a tree and implement a TreeSelectionListener:
my mission is whenever i select a node i need to change the icon of this node (for now.later i will have to find if it have childrens).
import java.awt.Color;
import java.awt.Component;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import java.util.Vector;
import javax.swing.ImageIcon;
import javax.swing.JTree;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeExpansionListener;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
public class TreeView{
     DefaultMutableTreeNode top;
     JTree tree ;
     Color frameColor;
     public static ImageIcon NoTSelIcon;
     public static ImageIcon SelIcon;
    public static String[] name= new String[8];
     public TreeView(Color BackColor) {
          // TODO Auto-generated constructor stub
        top =  new DefaultMutableTreeNode("Diagnostics");
        this.frameColor=BackColor;
         SelIcon = createImageIcon("../Resource/Images/Select.gif");
         if (SelIcon == null)
             System.err.println("Tutorial icon missing; using default.");
         NoTSelIcon = createImageIcon("../Resource/Images/NotSelc.gif");
           if (NoTSelIcon == null)
             System.err.println("Tutorial icon missing; using default.");
     public Component createTreeComponents(){
            //Create the nodes.
             createNodes(top);
        //Create a tree that allows one selection at a time.
        tree = new JTree(top);
        //TREE LISTENERS
        //Treeselction listener
        Handler hObject = new Handler();
        tree.addTreeSelectionListener(hObject);
       //Tree expand/collapse listener
        HandlerExpansionListener hObjectExpan = new HandlerExpansionListener();
        tree.addTreeExpansionListener(hObjectExpan);
//       tree.getSelectionModel().setSelectionMode(TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION);
        //set tree background
        tree.setBackground(frameColor);
         tree.setCellRenderer(new OverrideTreeCellRenderer(frameColor,SelIcon,NoTSelIcon));
        return tree;
      private void createNodes(DefaultMutableTreeNode top) {
             DefaultMutableTreeNode category = null;
             DefaultMutableTreeNode SubCategory = null;
             DefaultMutableTreeNode SubCategoryBasee = null;
             DefaultMutableTreeNode SubSubCategoryBasee = null;
             category = new DefaultMutableTreeNode("Dfe");
             top.add(category);
             //Sub test visible
             SubCategory = new DefaultMutableTreeNode("Test Visible");
             category.add(SubCategory);
             SubCategory.add(new DefaultMutableTreeNode("Son 1"));
             SubCategory.add(new DefaultMutableTreeNode("Son 2"));
             SubSubCategoryBasee = new DefaultMutableTreeNode("Test Base");
             SubSubCategoryBasee.add(new DefaultMutableTreeNode("Grandson 1"));
             SubSubCategoryBasee.add(new DefaultMutableTreeNode("Grandson 2"));
             SubCategory.add(SubSubCategoryBasee);
      class Handler implements TreeSelectionListener {
               public void valueChanged(TreeSelectionEvent arg0) {
                    // TODO Auto-generated method stub
                    System.out.println("treeSelect event ");
                    TreePath trph;
                    trph=arg0.getNewLeadSelectionPath();
                    int count=trph.getPathCount();
                    DefaultMutableTreeNode Selnode = (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
                    String Name = (String)Selnode.getUserObject();
                    setSelected(Selnode,true);
                    int number_ofnodes=getNodeCountBelow((TreeModel)tree.getModel() , Selnode, false);
                    System.out.println("The Number of nodes under "+Name+"="+number_ofnodes);
                    tree.setCellRenderer(new IconRenderer(SelIcon,NoTSelIcon,frameColor));
      class HandlerExpansionListener implements TreeExpansionListener {
               public void valueChanged(TreeSelectionEvent arg0) {
                    // TODO Auto-generated method stub
                    DefaultMutableTreeNode node = (DefaultMutableTreeNode)  tree.getLastSelectedPathComponent();
                    if (node == null) return;
                  }     // The inner class
               public void treeCollapsed(TreeExpansionEvent arg0) {
                    // TODO Auto-generated method stub
                    System.out.println("treeCollapsed event ");
               public void treeExpanded(TreeExpansionEvent arg0) {
                    // TODO Auto-generated method stub
                    System.out.println("treeExpanded event ");
      /** Returns an ImageIcon, or null if the path was invalid. */
         protected static ImageIcon createImageIcon(String path) {
              //ImageIcon imcon= new ImageIcon(path);
              //return imcon;
             java.net.URL imgURL = TreeView.class.getResource(path);
             if (imgURL != null) {
                 return new ImageIcon(imgURL);
             } else {
                 System.err.println("Couldn't find file: " + path);
                 return null;
         DefaultMutableTreeNode newnode;
         public void setSelected(DefaultMutableTreeNode Selnode ,boolean isSelected)
                Enumeration Enchilds=Selnode.children();//ENUMRATE ALL CHILDS FOR THIS NODE
             if (Enchilds != null)
                  while (Enchilds.hasMoreElements())
                       newnode=(DefaultMutableTreeNode)Enchilds.nextElement();
                       String NameSel = (String)newnode.getUserObject();
                       setSelected(newnode,isSelected);
         //GETTING THE TREE DEPTH
         public int getNodeCountBelow(TreeModel model, Object node, boolean includeInitialNode)
             int n = includeInitialNode ? 1 : 0;
             for (int i = 0; i < model.getChildCount(node); i ++)
                 n += getNodeCountBelow(model, model.getChild(node, i), true);
             return n;
import java.awt.Color;
import java.awt.Component;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import javax.swing.Icon;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
public class IconRenderer extends DefaultTreeCellRenderer {
     private static final long serialVersionUID = 1L;
     Icon SelectedIcon;
     Icon NotSelectedIcon;
     Color BackgroundColor;
     boolean Selected=false;
     boolean Leaf=false;
     boolean IsItaChild=false;
     DefaultMutableTreeNode SelctedNode=null;
    public IconRenderer(Icon SelIcon,Icon NoTSelIcon,Color Bacground) {
         SelectedIcon = SelIcon;
         NotSelectedIcon = NoTSelIcon;
         BackgroundColor=Bacground;
         setBackgroundNonSelectionColor(BackgroundColor);
    public Component getTreeCellRendererComponent(JTree tree,Object value,boolean sel,boolean expanded,
                                                    boolean leaf,int row,boolean hasFocus)
         super.getTreeCellRendererComponent(tree, value, sel,expanded, leaf, row,hasFocus);
         Selected=sel;
         Leaf=leaf;
         DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
         String s2 = (String)node.getUserObject();
   return this;
}my problem is :
when i select a node the the method "getTreeCellRendererComponent"
start to run on the entire tree from buttom to top and than from top to buttom.
for me it waste of time because if has say 100 nodes it wont botthers me.
but i have 20000 nodes and more its take a time.
and for all this nodes i have to make compares.
is there a way to force the DefaultTreeCellRenderer to not run the entire tree???
Thanks

Answer 1

You need to make sure that your TreeModel interprets your group nodes to be non-leaf nodes (one of the methods in the TreeModel interface is called isLeaf). If you are using a DefaultTreeModel with DefaultMutableTreeNode objects, you can use the askAllowsChildren property of DefaultTreeModel and the allowsChildren property of DefaultMutableTreeNode to control this. See the API for more details:
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/tree/DefaultTreeModel.html
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/tree/DefaultMutableTreeNode.html