Java Custom Tree Model updating problem

Question

Here is structure of the tree:

root -branches --leafs

I use for TreeModel DefaultTreeModel and my objects implement TreeNode interface

leaf is some Object:

public class Leaf implements TreeNode
{
   // implementation

branch has List of leafs:

public class Branch implements TreeNode
{
 private List<Leaf> leafs;

 // implementation

And root is container of branches:

public class Root implements TreeNode
{
  private List<Branch> branches;

  // implementation

When I add new leaf, my tree doesn't updated, when I add leaf and create new DefaultTreeModel with my root object it's updated. I watch DefaultMutableTreeNode implementation, there isn't any event firing on inserting childs... What am I doing wrong? Before, I tried to implement TreeModel interface wich looks much better then implementing TreeNode interface for three classes, but result was similar. I also read about GlazedLists, but I dislike their tree conception. For me, the best is implementation TreeModel interface conception, but how to update model when some inner List in model add new element?...

Answer 1

Without seeing the code, it's hard to be sure - nevertheless I'll bet on my guess: you don't notify the TreeModel about your insertions ;-)

A code snippet of what you have to do if your node implementation is not of type MutableTreeNode:

 // do the parent wiring in your custom TreeNode
 int position = myBranch.addChild(node);
 // notify the model 
 model.nodesWhereInserted(myBranch, new int[] {pos}); 

If it is of type MutableTreeNode, the easier way is via the convenience methods in DefaultTreeModel

 model.insertNodeInto(node, myBranch, position)

Answer 2

that look like as issue with Concurrency in Swing, maybe updates are out of EDT,

you have add new Object, then to test DefaultTreeModel if contains new Object, if Objects exists, then you have to wrap (all updates) into invokeLater, for Serializable or Observate would be better look for invokeAndWait