JTree genius needed

Question

I need some serious help with the JTree as I am very confused as to why my tree is behaving in a certain manner. Basically I have saw AbstractTreeModel.java ina thread on thsi forum which emplements TreeModel. My tree is populated by data coming into the application over a network stream.
Basically whats going on is, I am able to insert nodes and in fact change the valeu of nodes while the
parent node above the node i am inserting is collapsed.Once the node is expanded I can change the value(in this case teh color of the icon) of the node, but the new nodes being inserted in the tree do not show up.
Very confusing! I mean I see the same behavior when the parent is expanded or collapsed. But The nodes do not apear when the parent is expanded. In fact, after expanding and collapsing they no longer appear at all. What happens to my applciation when the node is expanded???
Any thoughts

Answer 1

Thanks for replying. I tried to do what you said. I think it would be best if i sent you some code.
Here is my model which extends yours.
public class ResourceTreeModel extends AbstractTreeModel {
Vector listeners;
public ResourceTreeModel(ResourceTypeNode r) {
if(r == null) {
throw new IllegalArgumentException("Root is null.");
setRoot(r);
/*This method adds
*the new ResourceNode to
*the tree model with
*the specified ResourceTypeNode
*as the parent.
public void nodeInserted(ResourceTypeNode parent, Object node, int index) {
//Resource type nodes
//are where we insert
//ResourceNodes
if(node instanceof ResourceTypeNode) {
parent.setChild(index, node);
else if(node instanceof ResourceNode) {  
parent.setChild(index, node);
else {
index = getIndexOfChild((Object)parent, node);
TreePath tp = new TreePath(getPathToRoot(node));
int[] ai = { index };
Object[] ac = {node};
fireTreeNodesInserted(new TreeModelEvent(this, tp, ai, ac));
public void nodeChanged(Object node) {
TreePath tp = new TreePath(getPathToRoot(node));
fireTreeNodesChanged(new TreeModelEvent(this, tp, null, null));
public Object getChild(Object parent, int index) {
if(parent instanceof ResourceTypeNode) {
return ((ResourceTypeNode)parent).getChildAt(index);
return null;
* Returns the number of children of parent.
* @param parent the parent node
* @return the child count
public int getChildCount(Object parent) {
if(parent instanceof ResourceTypeNode) {
return ((ResourceTypeNode)parent).getChildCount();
return 0;
* Returns the index of child in parent.
* @param parent the parent node
* @param child the child node
* @return the index of the child node in the parent
public int getIndexOfChild(Object parent, Object child) {
if(parent instanceof ResourceTypeNode && child instanceof ResourceTypeNode ) {
return ((ResourceTypeNode)parent).getIndex((ResourceTypeNode)child);
else if(parent instanceof ResourceTypeNode && child instanceof ResourceNode ) {
return ((ResourceTypeNode)parent).getIndex((ResourceNode)child);
else {
return -1;
public Object getParent(Object obj) {
Object parent = null;
if(obj instanceof ResourceTypeNode) {
parent = ((ResourceTypeNode)obj).getParent();
else if(obj instanceof ResourceNode) {
parent = ((ResourceNode)obj).getParent();
else {
return parent;
public boolean isLeaf(Object node) {
return (node instanceof ResourceNode);
Here is the class in which i build my tree at the start of application
/*Create the apprpriate
*ResourceTypeNodes for
*the tree. The keys from
*the C2App.resourceTypes
*TreeMap are used to create
*the JTree nodes.
*A StringTokenizer is used
*to dissect the segments
*of the resource names
*to build category nodes.
public void init() {
root = new ResourceTypeNode("Resources");
treeModel = new ResourceTreeModel(root);
//Need set of names
//for resources.
Set rTypesKeySet = C2App.resourceTypes.keySet();
Iterator iter = rTypesKeySet.iterator();
ResourceTypeNode key = null;
ResourceTypeNode category = null;
//Iterate through
//all types.
while(iter.hasNext()) {
//Full Resource
//Type Name.
String currentCategory = iter.next().toString();
//Need to determine the
//level from root this
//node should go into.
StringTokenizer stok = new StringTokenizer(currentCategory, "::");
//Levels from
//root to node
//to create.
int levelFromRoot = stok.countTokens();
//Node goes under
//root parent node.
if(currentCategory.lastIndexOf("::") == -1) {
resourceTypeNodes.put(currentCategory, new ResourceTypeNode(currentCategory));
ResourceTypeNode parent = root;
parent.add((ResourceTypeNode)resourceTypeNodes.get(currentCategory));
treeModel.nodeInserted(parent, resourceTypeNodes.get(currentCategory), parent.getChildCount());
//Node goes under
//a parent node other
//than root.
else {
resourceTypeNodes.put(currentCategory, new ResourceTypeNode(currentCategory));
String parentName = Resource.parentOf(currentCategory);
ResourceTypeNode parent = (ResourceTypeNode)resourceTypeNodes.get(parentName);
parent.add((ResourceTypeNode)resourceTypeNodes.get(currentCategory));
treeModel.nodeInserted(parent, resourceTypeNodes.get(currentCategory), parent.getChildCount());
This works fine I am able to open app and see all the resourcetype nodes wich are not leaves
the problem i am having is with the code snippet below.
//Existing resource?
if(existingResource) {
//Change value
//of node
((ResourceTreeModel)C2App.theGUI.resourceTreePanel.resourceTree.getModel()).nodeChanged(C2App.theGUI.resourceTreePanel.resourceNodes.get(resourceID));
//Is this node
//displayed in
//the ResourceInfoPanel?
if(ResourceInfoPanel.getResourceDisplayedID().equals(resourceID)) {
//Update panel.
c2app.gui.ResourceInfoPanel.updatePanel(r);
//New resource
//for tree?
else {
//Get type so
//that we can
//decide which
//parent node
//the node should
//be placed under.
String type = r.type;
//Get Parent node.
ResourceTypeNode parent = (ResourceTypeNode)C2App.theGUI.resourceTreePanel.resourceTypeNodes.get(type);
//Insert node
//into tree under
//parent.
parent.add((ResourceNode)C2App.theGUI.resourceTreePanel.resourceNodes.get(resourceID));
((ResourceTreeModel)C2App.theGUI.resourceTreePanel.resourceTree.getModel()).nodeInserted(parent, C2App.theGUI.resourceTreePanel.resourceNodes.get(resourceID), parent.getChildCount());
//Expand path
//to this node
/*Object[] tn = ((ResourceTreeModel)(C2App.theGUI.resourceTreePanel.resourceTree.getModel())).getPathToRoot(parent);
System.out.println();
for(int j = 0; j < tn.length; j++) {
System.out.println("TN: " + tn[j].toString());
System.out.println();
TreePath tp = new TreePath(tn);
System.out.println();
System.out.println("TP: " + tp.toString());
System.out.println();
C2App.theGUI.resourceTreePanel.resourceTree.expandPath(tp);*/
//((ResourceTreeModel)(C2App.theGUI.resourceTreePanel.resourceTree.getModel())).reload();
//C2App.theGUI.resourceTreePanel.expandTree();
C2App.theGUI.resourceTreePanel.resourceTree.treeDidChange();
//Update the map.
break;
basically if the node row is collapsed which i am adding to the add occurs.
but if it is expanded i do not see the new node.
Funny that the update of the node occurs if existing resource is true.
So that makes me wonder why nodeChanged works but not nodeInserted
i analyzed all the way down to fireTreeNodesInserted with println and it is being called it tells me nod eis being added
d not understand why when node is expanded cant add child to it.
Thanks again I hope you can help me
Vinny