Help with FileTreePanel Modification

Question

Is it possible to turn these labels into check boxes?
import java.awt.BorderLayout;
import java.awt.Component;
import java.io.File;
import java.util.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.filechooser.FileSystemView;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.TreeNode;
* @author Kirill Grouchnikov
public class FileTreePanel extends JPanel {
      * File system view.
     protected static FileSystemView fsv = FileSystemView.getFileSystemView();
      * Renderer for the file tree.
      * @author Kirill Grouchnikov
     private static class FileTreeCellRenderer extends DefaultTreeCellRenderer {
           * Icon cache to speed the rendering.
          private Map<String, Icon> iconCache = new HashMap<String, Icon>();
           * Root name cache to speed the rendering.
          private Map<File, String> rootNameCache = new HashMap<File, String>();
           * (non-Javadoc)
           * @see javax.swing.tree.DefaultTreeCellRenderer#getTreeCellRendererComponent(javax.swing.JTree,
           *      java.lang.Object, boolean, boolean, boolean, int, boolean)
          @Override
          public Component getTreeCellRendererComponent(JTree tree, Object value,
                    boolean sel, boolean expanded, boolean leaf, int row,
                    boolean hasFocus) {
               FileTreeNode ftn = (FileTreeNode) value;
               File file = ftn.file;
               String filename = "";
               if (file != null) {
                    if (ftn.isFileSystemRoot) {
                         // long start = System.currentTimeMillis();
                         filename = this.rootNameCache.get(file);
                         if (filename == null) {
                              filename = fsv.getSystemDisplayName(file);
                              this.rootNameCache.put(file, filename);
                         // long end = System.currentTimeMillis();
                         // System.out.println(filename + ":" + (end - start));
                    } else {
                         filename = file.getName();
               JLabel result = (JLabel) super.getTreeCellRendererComponent(tree,
                         filename, sel, expanded, leaf, row, hasFocus);
               if (file != null) {
                    Icon icon = this.iconCache.get(filename);
                    if (icon == null) {
                         // System.out.println("Getting icon of " + filename);
                         icon = fsv.getSystemIcon(file);
                         this.iconCache.put(filename, icon);
                    result.setIcon(icon);
               return result;
      * A node in the file tree.
      * @author Kirill Grouchnikov
     private static class FileTreeNode implements TreeNode {
           * Node file.
          private File file;
           * Children of the node file.
          private File[] children;
           * Parent node.
          private TreeNode parent;
           * Indication whether this node corresponds to a file system root.
          private boolean isFileSystemRoot;
           * Creates a new file tree node.
           * @param file
           *            Node file
           * @param isFileSystemRoot
           *            Indicates whether the file is a file system root.
           * @param parent
           *            Parent node.
          public FileTreeNode(File file, boolean isFileSystemRoot, TreeNode parent) {
               this.file = file;
               this.isFileSystemRoot = isFileSystemRoot;
               this.parent = parent;
               this.children = this.file.listFiles();
               if (this.children == null)
                    this.children = new File[0];
           * Creates a new file tree node.
           * @param children
           *            Children files.
          public FileTreeNode(File[] children) {
               this.file = null;
               this.parent = null;
               this.children = children;
           * (non-Javadoc)
           * @see javax.swing.tree.TreeNode#children()
          public Enumeration<?> children() {
               final int elementCount = this.children.length;
               return new Enumeration<File>() {
                    int count = 0;
                     * (non-Javadoc)
                     * @see java.util.Enumeration#hasMoreElements()
                    public boolean hasMoreElements() {
                         return this.count < elementCount;
                     * (non-Javadoc)
                     * @see java.util.Enumeration#nextElement()
                    public File nextElement() {
                         if (this.count < elementCount) {
                              return FileTreeNode.this.children[this.count++];
                         throw new NoSuchElementException("Vector Enumeration");
           * (non-Javadoc)
           * @see javax.swing.tree.TreeNode#getAllowsChildren()
          public boolean getAllowsChildren() {
               return true;
           * (non-Javadoc)
           * @see javax.swing.tree.TreeNode#getChildAt(int)
          public TreeNode getChildAt(int childIndex) {
               return new FileTreeNode(this.children[childIndex],
                         this.parent == null, this);
           * (non-Javadoc)
           * @see javax.swing.tree.TreeNode#getChildCount()
          public int getChildCount() {
               return this.children.length;
           * (non-Javadoc)
           * @see javax.swing.tree.TreeNode#getIndex(javax.swing.tree.TreeNode)
          public int getIndex(TreeNode node) {
               FileTreeNode ftn = (FileTreeNode) node;
               for (int i = 0; i < this.children.length; i++) {
                    if (ftn.file.equals(this.children))
                         return i;
               return -1;
          * (non-Javadoc)
          * @see javax.swing.tree.TreeNode#getParent()
          public TreeNode getParent() {
               return this.parent;
          * (non-Javadoc)
          * @see javax.swing.tree.TreeNode#isLeaf()
          public boolean isLeaf() {
               return (this.getChildCount() == 0);
     * The file tree.
     public JTree tree;
     * Creates the file tree panel.
     public FileTreePanel() {
          this.setLayout(new BorderLayout());
          File[] roots = File.listRoots();
          FileTreeNode rootTreeNode = new FileTreeNode(roots);
          this.tree = new JTree(rootTreeNode);
          this.tree.setCellRenderer(new FileTreeCellRenderer());
          this.tree.setRootVisible(false);
          final JScrollPane jsp = new JScrollPane(this.tree);
          jsp.setBorder(new EmptyBorder(0, 0, 0, 0));
          this.add(jsp, BorderLayout.CENTER);
     public static void main(String[] args) {
          SwingUtilities.invokeLater(new Runnable() {
               public void run() {
                    JFrame frame = new JFrame("File tree");
                    frame.setSize(500, 400);
                    frame.setLocationRelativeTo(null);
                    frame.add(new FileTreePanel());
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    frame.setVisible(true);

Answer 1

I found this using Google, but I don't know how to go about doing it.
"Making a tree with check boxes has been done before and doing a web search will reveal several examples of such. Simply adding JCheckBox as the rendering component of the nodes is not enough since the rendering is static, and you have to manually add listeners to check and uncheck the box."