Question

Continuing with this I decided to take an approach of making a different entity and make a OneToOne relationship (I hope this is OK). Bet let me explain what I have been doing:

I have a Juez (judge) entity with these relevant fields:

@Entity
@Table(name = "jueces")
public class Juez implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    @Column(name = "id")
    private Integer id;

    @Version
    @Column(name = "opt_lock")
    private Integer version;

    @Basic
    @Column(name = "nombres")
    private String nombres;

    // Getters, setters, other properties, etc.

}

And I want another entity called RolDeJueces (judge roll) to hold a java.util.Map<Integer, Juez> in which I want the keys to be sorted (1,2,3…) and mapped to a judge so I can have a roll to make some calculations. Here is what I have until now:

@Entity
@Table(name = "rol_jueces")
public class RolDeJueces {

     @Id
     private Integer id;

     @Version
     @Column(name = "opt_lock")
     Integer version;

     @OneToMany //Is this ok?
     @MapKeyColumn(name = "orden_juez", updatable = true)
     private Map<Integer, Juez> rol;

     // Getters, setters, other properties, etc.

}

How can I sort the map key and hold a reference to all my judges but only one time (a la @OneToOne)?

Also, I must be capable of reordering my judges and make the changes persistent e.g.

rolDeJueces.getRol().clear(); // Delete current order
int order = 0;
// Add judges according to new order to the roll
for(Juez juez : getNewOrder()){
    RolDeJueces.getRol().put(++order, juez);
}

// save my new roll and stuff...

Is this possible?

Answer 1

Ok, I figured that I do not need a map for insertion order nor the stuff I wanted.

Here is the impl:

 @Id
 @GeneratedValue(strategy = GenerationType.TABLE)
 private Integer id;

 @Version
 @Column(name = "opt_lock")
 private Integer version;

 @OneToMany(orphanRemoval = false)
 @OrderColumn(name = "order_jueces")
 private List<Juez> rol;

@OrderColumn will generate an extra column in the table used for the relationship.