public void drop() {
        for (byte i = 0; i < 16; ++i) {
            for (byte j = 0; j < 16; ++j) {
                File file = new File(getFullName(new DirFile(i, j)));
                if (file.exists()) {
                    if (!file.delete()) {
                        throw new DataBaseException("Cannot delete a file!");
                    }
                }
            }
            tryDeleteDirectory(Integer.toString(i) + ".dir");
        }
        if (!new File(dataBaseDirectory, "signature.tsv").delete()) {
            throw new DataBaseException("Cannot delete a file!");
        }
    }