Get generated entity Id before persisting, Hibernate, Spring data

Question

Some preconditions:

I am not using Oracle DB sequence generator. Instead of it, I rely on the Hibernate sequence generator ex

@Entity
@Table(name = "JPA_ENTITY_A")
@GenericGenerator(name = "system-uuid", strategy = "uuid2")
public class JpaEntityA{
    @Id
    @Type(type = "uuid-binary")
    @GeneratedValue(generator = "system-uuid")
    private UUID id;
    @Column(name="NAME_WITH_ID")
    String nameWithGeneratedId;
}

What I want is to persist the following generated value into the column "NAME_WITH_ID": this.nameWithGeneratedId+this.id

Is it feasible to do the following:

public String getNameWithGeneratedId(){
    return this.nameWithGeneratedId+this.id;//hope that the returned value will be persisted
}

Or is it possible to retrieve in advance before persisting entity to the DB generated id? If yes, then how can I accomplish it? (based on the comments below it is not possible to do it)

Thx in advance.

Answer 1

You can't; the act of persisting itself is what creates the ID.

Answer 2

In your case, which uses a UUID generator, I think you can use the Lifecycle interface and implement the onSave method returning NO_VETO .

eg

@Entity
public MyEntity implements Lifecycle {

    @Id
    @GeneratedValue
    private UUID id;

   ...


    public boolean onSave(final Session session) throws CallbackException {
      // here your entity will have an ID
      return Lifecycle.NO_VETO;
    }

    ...

}

The onSave method will be called before saving the entity and after generating the ID.