public ArrayList<Book> searchBook(int searchType, String criterion) {
		ArrayList<Book> searchList = new ArrayList<>();
		for (Book book : bookList.getBookList()) {
			if (searchType == 0) {
				if (book.getTitle().contains(criterion)) {
					searchList.add(book);
				}
			} else if (searchType == 1) {
				if (book.getAuthor().contains(criterion)) {
					searchList.add(book);
				}
			} else if (searchType == 2) {
				if (book.getGenre().contains(criterion)) {
					searchList.add(book);
				}
			}
		}

		return searchList;
	}