How to recursively traverse JTree?

[Liana Norpunova]

Hi!

There is JTree component that I want to fill from the database. New nodes can be dynamically added to this tree. I need a procedure that will recursively traverse a tree. My problem is that only second-level nodes are added to the root node, but other-level nodes are not created. I've included System.out.println to see the results and problems. Please, help me to fix the error. Below is my code:

      public static void createTree() {
Vector ofTitles = new Vector();
ofTitles = returnDataFromSelectQuery("select title from Folders");
Object hierarchy[] = ofTitles.toArray();
 
Vector ofChildOf = new Vector();
ofChildOf = returnDataFromSelectQuery("select childOf from Folders");
Object hierarchyChildOf[] = ofChildOf.toArray();
      tree1 = new JTree(); tree1.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
      root = new DefaultMutableTreeNode(hierarchy[0]);
      treeModel = (DefaultTreeModel)tree1.getModel();
      treeModel.setRoot(root);
      traverse( hierarchy, hierarchyChildOf, 0 );
      ...
      }

public static void traverse( Object hierarchy[], Object hierarchyChildOf[], int k ) {
for(int i = 0; i < hierarchy.length; i++) {
  if (hierarchy[k].equals(hierarchyChildOf[i])) {
  MutableTreeNode childNode = new DefaultMutableTreeNode(hierarchy[i]);
  try { 
  TreePath path = tree1.getNextMatch(hierarchyChildOf[i].toString(), 0, Position.Bias.Forward);
  if (path != null) {
    MutableTreeNode parentNode = (DefaultMutableTreeNode)(MutableTreeNode) path.getLastPathComponent();
    treeModel.insertNodeInto(childNode, parentNode, parentNode.getChildCount());
    System.out.println("The child node " + hierarchy[i] + " is added to the parent node " + hierarchyChildOf[i]);
  } else {
    System.out.println("The path to the parent node " + hierarchyChildOf[i] + " cannot be found.");
  }
  } catch (Exception e) {
    e.printStackTrace();
  }
traverse(hierarchy, hierarchyChildOf, i);
}
}
}

The output produced by System.out.println:

      The child node Contracts is added to the parent node Documents
      The child node Correspondence is added to the parent node Documents
      The path to the parent node Correspondence cannot be found.
      The path to the parent node Correspondence cannot be found.
      The child node Inner documents is added to the parent node Documents
      The child node Labour contracts is added to the parent node Documents

Thanks a lot!

[Paul Clapham]

I would just call either the breadthFirstEnumeration() or the depthFirstEnumeration() method of the DefaultMutableTreeNode which is the root of the tree, if I wanted to traverse all the nodes of the tree model. I wouldn't bother to write my own code.

But what I actually do is to have the user object contain a link to the node which contains it. That way there's no searching required at all.

[Liana Norpunova]

Well, probably my question is a bit unclear. I want to ADD nodes to the JTree, and not only search them.

Initially, I have a data set stored in the database and a BLANK JTree. This data set contains a tree structure, e.g.:
1. Documents
1.1 Correspondence
1.1.1 Incoming
1.1.2 Outgoing
1.2 Contracts
etc.

What I need, is to build the JTree based on the above-shown information.

So, does the depthFirstEnumeration() method of the DefaultMutableTreeNode provides possibilities to ADD nodes?