private Book createBookByNode(Node bookNode) throws Exception {
    if (bookNode == null) {
      return null;
    }

    Book bookNew = new Book();
    bookNew.setId(bookNode.getName());

    PropertyReader reader = new PropertyReader(bookNode);
    bookNew.setName(reader.string(BookNodeTypes.EXP_BOOK_NAME));
    bookNew.setCategory(
        Utils.bookCategoryStringToEnum(reader.string(BookNodeTypes.EXP_BOOK_CATEGORY)));
    bookNew.setContent(reader.string(BookNodeTypes.EXP_BOOK_CONTENT));
    return bookNew;
  }