public TreePath getParentPath() { return new TreePath(this.getPath(), path.length - 1); }
public TreePath getParentPath() {   if (path.length <= 1) return null;  return new TreePath(this.getPath(), path.length - 1); }
	public TreePath getParentPath() {		return new TreePath(this.getPath(), path.length - 1);	} // getParentPath()