如何在Java中用复选框显示目录结构？

Question

我想在树中显示目录结构：

public static void main(String[] args) {
    File sourceDirectory = new File("C:\\myFolder");
    DefaultMutableTreeNode sourceRoot = new DefaultMutableTreeNode(sourceDirectory);

    DefaultTreeModel sourceModel = new DefaultTreeModel(sourceRoot);
    JTree sourceTree = new JTree();

    sourceTree.setModel(sourceModel);
    sourceTree.setShowsRootHandles(true);

    sourceRoot.removeAllChildren();
    sourceModel.reload();
    File rootFile = (File) sourceRoot.getUserObject();

    addFiles(rootFile, sourceModel, sourceRoot);
}

    protected void addFiles(File rootFile, DefaultTreeModel model, DefaultMutableTreeNode root) {
    for (File file : rootFile.listFiles()) {
        DefaultMutableTreeNode child = new DefaultMutableTreeNode(file.getName());
        model.insertNodeInto((MutableTreeNode) child, root, root.getChildCount());
        if (file.isDirectory()) {
            addFiles(file, model, child);
        }
    }
}

结果就是这些：

但是我想为每个树项添加复选框，我该怎么办？