Model <-> Entity

@Entity
public class AuthorEntity {
   @Id
   private Long authorId;
   @OneToOne
   @JoinTable(name="author_book",
      joinColumns={@JoinColumn(name="authorKey", referencedColumnName="authorId")},
      inverseJoinColumns={@JoinColumn(name="bookKey", referencedColumnName="bookId")})
   private BookEntity bookEntity;
 
   @Builder
   public AuthorEntity(Long authorId, BookEntity bookEntity) {
      this.authorId=authorId;
      this.bookEntity=bookEntity;
   }
}

@Entity
public class BookEntity {
   @Id
   private Long bookId;
   @OneToOne(mappedBy="author")
   private AuthorEntity authorEntity;
 
   @Builder
   public BookEntity(Long bookId, AuthorEntity autorEntity) {
      this.bookId=bookId;
      this.authorEntity=authorEntity;
   }
}

public record Author(Long authorId, Book book) {}

public record Book(Long bookId, Author author) {}

AuthorEntity authorEntity = jpaAuthorRepo.findById(id);
return new Author(
   authorEntity.getAuthorId();
   [B]???[/B] [I]просто присвоить значение authorEntity.getBookEntity() я не могу, т.к. тут нужна модель Book[/I]
);

public record Author(Long authorId, Long bookId) {}

public record Book(Long bookId, Long authorId) {}

public record Author(Long authorId) {}

public record Book(Long bookId, Long authorId) {}