Adding nodes to specific positions of JTree

Question

Hi guys, I have a JTree that basically represents a file explorer with all the folders and files in a drive. I want to automatically refresh the tree if there are any new files added to that drive. What my idea was to:
1. Set a timer to check the list of files in that directory every 1 second
2. If there are any changes, I would obtain the path of the file
3. Create a new DefaultMutableTreeNode for that file
4. Add this node into the JTree.
The problem I have right now is that all the debug checks are printing the right stuffs. However, JTree doesn't add the new node if files are placed in a sub folder, or a folder is copied into the directory. The code is not ready to detect file deletion yet.
Here is my code:
public static void refresh(final File dir, final JTree fileTree)
     //Start the timer
     final Timer timer = new Timer(1000, new ActionListener()
          //Get a list of the files
          List<File> listA = new ArrayList<File>(listAllFiles(null, dir, 2));
          public void actionPerformed(ActionEvent ae)
               int c = 0;
               List<File> listB = new ArrayList<File>(listAllFiles(null, dir, 2));
               //Files added
               if (listA.size() < listB.size())
                    File[] files = new File[listB.size() - listA.size()];
                    //Find out which file is it
                    for (int i = 0; i < listB.size(); i++)
                         //File found
                         if (!listA.contains(listB.get(i)))
                              //Get all the new files into an array
                              files[c] = (File) listB.get(i);
                              c++;
                    //Update the list first
                    listA = listB;
                    //Update each file into the file tree
                    for (int i = 0; i < files.length; i++)
                         //Remove user.dir path
                         String filePath = files.getAbsolutePath();
                         String userDir = System.getProperty("user.dir");
                         filePath = filePath.substring(userDir.length() + 1, filePath.length());
                         //Convert path separator to / for splitting
                         if (System.getProperty("os.name").contains("Windows"))
                              filePath = filePath.replaceAll("\\\\", "/");
                         //Convert it to tree path
                         Object root = ((DefaultTreeModel)fileTree.getModel()).getRoot();
                         String str[] = filePath.split("/");
                         Object obj[] = new Object[str.length];
                         obj[0] = root;
                         for (int j = 0; j < str.length - 1; j++)
                              obj[j + 1] = new DefaultMutableTreeNode(str[j]);
                         TreePath path = new TreePath(obj);
                         //New node to be added into the fileTree
                         DefaultMutableTreeNode newNode = new DefaultMutableTreeNode(files[i].getName());
                         DefaultMutableTreeNode parentNode = (DefaultMutableTreeNode)path.getLastPathComponent();
                         ((DefaultTreeModel)fileTree.getModel()).insertNodeInto(newNode, parentNode, parentNode.getChildCount());
     timer.start();

Answer 1

bumps..