private void addEmptyThings(){
        SortedSet<String> keys = new TreeSet<String>(data.keySet());
        for (String path : keys) {
            while(true){
                path = deleteLastLevel(path);
                if(path == null || path.equals("")) {
                    break;
                }
                if(data.get(path) == null){
                    data.put(path, " ");
                }
            }
        }
    }