@Override
	public boolean updateBook(Book book) {
		if (doc == null)
			return false;
		Element currRoot = doc.getRootElement();
		Element parentBooks = currRoot.getChild("books");

		for (Element currBook : parentBooks.getChildren()) {
			String isbn = currBook.getChild("isbn").getText();
			if (book.getIsbn().equals(isbn)) {
				currBook.getChild("author").setText(book.getAuthor());
				currBook.getChild("title").setText(book.getTitle());
				currBook.getChild("price").setText(book.getPrice() + "");
				return true;
			}
		}

		return false;
	}