Refreshing JTree with a customized TreeModel

Question

Hello,
I'm newer to Swing, and I'm seeking for help for a JTree problem.
I hoped to display an XML document with JTree. So I customized a TreeModel and TreeNode to handle the XML data.
I used DOM to handle XML, and define TreeNode with the following class:
class DOMtoTreeNode {
org.w3c.dom.Node domNode;
public DOMtoTreeNode(org.w3c.dom.Node myNode){
this.domNode = myNOde; }
public String toString() {
//the displaying code
//and other necessary code to handle children of domNode
Then I defined an implementation of the TreeModel Interface.
public class DomTreeModel implements javax.swing.tree.TreeModel
Document document;
public DomTreeModel(Document aDomDoc){   
     this.document = aDomDoc;
// Basic TreeModel operations
I didn't define any personal TreeModelListener for this TreeModel
and then I created a JTree object to display the XML tree
treeModel = new DomTreeModel(someDOMDocument);
treeInputParameter = new JTree( treeModel );
and I defined JtreeListener.
What I hoped to do is to make modification for the XML document in the JTree.
I added the editing functions in the "valueChanged" function. I added a new DOM node as a child of an existing element node by directly append the child in the DOM node. The code is like the follows:
DOMToTreeNode treeNodeSelected =(DOMToTreeNode)
treeInputParameter.getLastSelectedPathComponent();
org.w3c.dom.Node domNode = treeNodeSelected.getNode();
//get the dom node from Jtree Node here
domNode.appendChild(someChildDomNode);
Up to now, it seems work fine. The TreeModel updates the DOM Document, and the modification being shown in JTree.
But when I tried to replace an existing node with a new node, something went wrong.
domNode.replace(newChild, oldChild);
I debugged the code, and found the underlying DOM Document in the TreeModel had been successfully changed, but the TreeModel didn't update the display in JTree.
I'm afraid this is quite a naive question, but would someone be kindly help me deal with this? It seems that the reason is that some code is missing to let the TreeModel refresh the frontend JTree display. But I realy don't know how to tackle this.
Thanks!
Haoxiang Xia

Answer 1

Thank you for your reply.
Are you adding nodes or just expanding the JTree?Adding nodes (I also want to delete nodes)
I don't know how to do this by just implementing
TreeModel. This is using DefaultTreeModel.Yeah, I really don't want to use DefaultTreeModel because I would have to wrap my data objects as TreeNodes. Since my data objects are already in a tree structure, implementing TreeModel is much cleaner.
It looks like I have to implement fireTreeNodesInserted() in my TreeModel, but I guess what I need to understand is how to register the JTree as a listener to my custom TreeModel. JTree doesn't directly implement TreeModelListener. I read somewhere that JTree automatically registers itself with the TreeModel, but that is not what I am observing.
So..., I am still in need of more info.