@Override
	public boolean deleteBook(Book book) {
		if (doc == null)
			return false;

		Element currRoot = doc.getRootElement();
		Element books = currRoot.getChild("books");
		List<Element> listBooks = books.getChildren();
		if (book.getLoanList() != null)
			for (Loan item : book.getLoanList()) {
				if (!deleteLoan(item)) {
					return false;
				}
			}

		for (Element currBook : listBooks) {
			String isbn = currBook.getChild("isbn").getText();
			if (book.getIsbn().equals(isbn)) {
				books.removeContent(currBook);
				return true;
			}
		}
		return false;
	}