How to update embedded objects in spring mongodb - spring

Question

I am working a simple Spring MongoDB implementation.
My Entities look like this:
#Document(collection = "Book")
public class Book {
#Id
private ObjectId id; // Note: This should be BinInt, String or ObjectId
private List<Author> author;
#Indexed // Note: On which fields we write where clause
private String bookName;
private int price;
private int rating;
private Date publishedDate;
private Map<String, String> contentIndex = new HashMap<>();
private List<String> tags;
private Publisher publisher;
#PersistenceConstructor
public Book(ObjectId id, List<Author> author, String bookName, String firstName, String lastName, int price, int rating, Date publishedDate, Map<String, String> contentIndex, List<String> tags, Publisher publisher) {
}
#Data
public class Publisher {
#Id
private ObjectId id;
private String firstName;
private String lastName;
private int bookCount;
private Date dob;
private String email;
#PersistenceConstructor
public Publisher(ObjectId id, String firstName, String lastName, int bookCount, Date dob, String email) {
}
#Data
public class Author {
#Id
private ObjectId id;
private String firstName;
private String lastName;
private String email;
private int bookCount;
private Date dob;
#PersistenceConstructor
public Author(ObjectId id, String firstName, String lastName, int bookCount, Date dob)
}
I am able to do all basic CRUD operations on BooK object by just extending the MongoRepositoy.
Now I am trying to do the same CRUD operations on embedded objects Publisher and array of Authors in the BooK object.
I am trying to do this but have not found a solution. I went through the Spring MongoDB documentation about Query and Update and several Stack Overflow questions. But not able to do it till now.
I am wanting to do the following things:
how to update field values in book.publisher object.
how to update book.authors[1] fields.
how to add new author to book.authors list object.

Answer 1

How to update field values in book.publisher object.
public void updatePublisher(BigInteger bookId, Publisher publisher) {
Query query = new Query();
query.addCriteria(Criteria.where("id").is(bookId));
Book book;
book = mongoTemplate.findOne
(query, Book.class);
Update update = new Update();
if (publisher.getFirstName() != null)
update.set("publisher.firstName", publisher.getFirstName());
if (publisher.getLastName() != null)
update.set("publisher.lastName", publisher.getLastName());
if (publisher.getBookCount() != null)
update.set("publisher.bookCount", publisher.getBookCount());
if (publisher.getEmail() != null)
update.set("publisher.email", publisher.getEmail());
mongoTemplate.findAndModify(query, update, Book.class);
}
How to update book.authors[1] fields.
public void updateAuthor(BigInteger bookId, Author author) {
Query query = new Query();
query.addCriteria(Criteria.where("id").is(bookId));
Book book;
book = mongoTemplate.findOne(query, Book.class);
Author old = null;
if (book != null) {
List<Author> al = book.getAuthors().getAuthors();
int index = -1;
for (int i = 0; i < al.size() && index == -1; i++) {
if (author.getId().equals(al.get(i).getId()))
index = i;
}
if (index > -1) {
old = book.getAuthors().getAuthors().get(index);
book.getAuthors().getAuthors().remove(index);
book.getAuthors().getAuthors().add(author); // Note: If you need merge of new object to old then , copy field by field from new object to old object.
mongoTemplate.save(book);
}
}
}
How to add new author to book.authors list object.
public Author addAuthor(BigInteger bookId, Author author) {
Query query = new Query();
query.addCriteria(Criteria.where("id").is(bookId));
Book book;
book = mongoTemplate.findOne
(query, Book.class);
if (book != null) {
book.getAuthors().getAuthors().add(author);
mongoTemplate.save(book);
}
return author;
}
I implemented and working well. However, I am open to optimising this if possible.