How to manage a One-To-One and a One-To-Many of same type as unidirectional mapping?
- by user1652438
I'm trying to implement a model for private messages between two or more users.
That means I've got two Entities:
User
PrivateMessage
The User model shouldn't be edited, so I'm trying to set up an unidirectional relationship:
@Entity (name = "User")
@Table (name = "user")
public class User implements Serializable {
@Id
String username;
String password;
// something like this ...
}
The PrivateMessage Model addresses multiple receivers and has exactly one sender. So I need something like this:
@Entity (name = "PrivateMessage")
@Table (name = "privateMessage")
@XmlRootElement
@XmlType (propOrder = {"id", "sender", "receivers",
"title", "text", "date", "read"})
public class PrivateMessage implements Serializable {
private static final long serialVersionUID = -9126766942868177246L;
@Id
@GeneratedValue
private Long id;
@NotNull
private String title;
@NotNull
private String text;
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private Date date;
@NotNull
private boolean read;
@NotNull
@ElementCollection(fetch = FetchType.EAGER, targetClass = User.class)
private Set<User> receivers;
@NotNull
@OneToOne
private User sender;
// and so on
}
The according 'privateMessage' table won't be generated and just the relationship between the PM and the many receivers is satisfied. I'm confused about this. Everytime I try to set a 'mappedBy' attribute, my IDE marks it as an error.
It seems to be a problem that the User-entity isn't aware of the private message which maps it.
What am I doing wrong here? I've solved some situation similar to this one, but none of those solutions will work here.
Thanks in advance!
