Confusion building JTree from path strings

Question

If I have a bunch of strings like this:
"/dira/dir1/file1"
"/dira/dir1/file2"
"/dira/dir2/file1"
"/dira/dir3/anotherdir/file1"
etc.
Does anybody have an easy solution to getting them in a JTree that looks like this:
   dira
    |
    +-dir1
    |  |
    |  +-file1
    |  |
    |  +-file2
    |
    +-dir2
    |  |
    |  +-file1
    |
    +-dir3
       |
       +-anotherdir
          |
          +-file1Mainly I am having trouble getting the tree to populate without duplicating nodes. For example dir1 gets listed twice. I am looking for a solution that will parse these strings and build the tree. I have found demos that read a file system, but nothing that works with strings. I have tried to pick apart the file system demos, but so far I can't get it to work correctly.
Thanks,
Jeff

Answer 1

This compiles and works (with 1.4):
import java.awt.*;
import javax.swing.*;
import javax.swing.tree.*;
import java.util.HashMap;
public class TreeStrings extends JFrame {
    public TreeStrings() {
        super("Tree strings");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(500, 400);
        String[] inputStrings = {"/dira/dir1/file1", "/dira/dir2/file1", "/dira/dir2/file2"}; // your bunch of Strings     
     DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("www");
     HashMap nodeMap = new HashMap();
     for(int i = 0; i < inputStrings.length; i++) {
         String s = inputStrings;
     DefaultMutableTreeNode lastNode = rootNode;
     int lastIndex = 0;
     while(true) {
          DefaultMutableTreeNode tempNode = null;
          int nextIndex = s.indexOf("/", lastIndex + 1); // <- i forgot + 1
          if(nextIndex != -1) { //we are somewhere in middle of s, checking nodes from root to leaf, one by one.
     String nodeKey = s.substring(0, nextIndex);
     if(nodeMap.get(nodeKey) == null) { //no such node, must make one
          String nodeName = s.substring(lastIndex, nextIndex); // you want the last nodeKey word for node name
     DefaultMutableTreeNode newNode = new DefaultMutableTreeNode(nodeName);
     nodeMap.put(nodeKey, newNode);
     lastNode.add(newNode);
     lastNode = newNode;
     else { //allready such node, just put it to be lastNode
     lastNode = (DefaultMutableTreeNode) nodeMap.get(nodeKey);
lastIndex = nextIndex;
     else { //no more "/" , it means we are at end of s, and that all parent nodes for this leaf-node exist.
     // and we just add the leaf node to last node
     String leafName = s.substring(lastIndex, s.length());
     DefaultMutableTreeNode leafNode = new DefaultMutableTreeNode(leafName);
     lastNode.add(leafNode);
     break; // go to next s
     //You first make your tree structure with DefaultMutableNodes,
     //Then make a DefaultTreeModel with the root node,
     //Then make a Tree with the DefaultTreeModel
     DefaultTreeModel treeModel = new DefaultTreeModel(rootNode);
JTree yourTree = new JTree(treeModel);
getContentPane().add(yourTree, BorderLayout.CENTER);
show();
public static void main(String[] args) {
     new TreeStrings();
Anything else?