I have three classes, User and Product, and their association class Order. I wanted to be able to add and delete rows in association table by editing Set in either User or Product. Adding is working, but when I remove some Orders from e.g. User, they are kept in DB.
Following this example I came up with this code.
@Getter
@Setter
@Entity
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
@OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
private Set<Order> orders;
public void setOrders(Set<Order> orders) {
this.orders = orders;
orders.forEach(order -> order.setUser(this));
}
}
@Getter
@Setter
@Entity
public class Product {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
@OneToMany(mappedBy = "product", cascade = CascadeType.ALL)
private Set<Order> orders;
public void setOrders(Set<Order> orders) {
this.orders = orders;
orders.forEach(order -> order.setProduct(this));
}
}
And association class:
@Getter
@Setter
@Entity
@NoArgsConstructor
public class Order {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@NotNull
@ManyToOne
@JoinColumn
private Product product;
@NotNull
@ManyToOne
@JoinColumn
private User user;
public Order(User user, Product product) {
this.user = user;
this.project = project;
}
@Override
public boolean equals(Object o){
if (this == o) return true;
if (!(o instanceof Order)) return false;
Engagement that = (Order) o;
return Objects.equals(user.getUsername(),
that.user.getUsername()) &&
Objects.equals(product.getName(),
that.product.getName());
}
@Override
public int hashCode(){
return Objects.hash(user.getUsername(),
product.getName());
}
}
in my OrderService class I add and edit set of Orders like this:
public addProductsToUser(User user, Set<Product> products){
Set<Order> orders = products.stream().map(product -> new Order(user, product)).collect(Collectors.toSet());
user.setOrders(orders);
userRepository.save(user); //save from CrudRepository
}
I expected that when I updated User it would also update Orders so that Orders that are not referenced anymore would be deleted, but I get multiple entries of Orders I kept.
