@Override
    public File nextOutputFolder() {
        if (!basedir.exists()) {
            basedir.mkdirs();
        }
        File[] files = basedir.listFiles(new FF());
        int no = 0;
        if (files != null && files.length > 0) {
            Arrays.sort(files, new Comparator<File>() {

                @Override
                public int compare(File o1, File o2) {
                    return Integer.parseInt(o1.getName()) - Integer.parseInt(o2.getName());
                }
            });
            no = Integer.parseInt(files[files.length - 1].getName()) + 1;
        }

        String filename = df.format(no);
        File nextFolder = new File(basedir, filename);
        return nextFolder;
    }