public void nodeAdded(String fqn) {
      MyNode n, p;

      n = root.add(fqn);
      if (n != null) {
        p = (MyNode) n.getParent();
        tree_model.reload(p);
        jtree.scrollPathToVisible(new TreePath(n.getPath()));
      }
    }
    public void nodeRemoved(String fqn) {
      MyNode n;
      TreeNode par;

      n = root.findNode(fqn);
      if (n != null) {
        n.removeAllChildren();
        par = n.getParent();
        n.removeFromParent();
        tree_model.reload(par);
      }
    }