I'd like to add a Date/DateTime/Timestamp field on an entity object, that will be automatically created when the entity is created/persisted and set to "now", never to be updated again.
Other use cases included fields that were always updated to contain the last modification date of the entity.
I used to achieve such requirements in the mysql schema.
What's the best way to do this in Play! / JPA?
There is a code snippet that you can adapt to achieve what you want. Take a look:
// Timestampable.java
package models;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;
import javax.persistence.PrePersist;
import javax.persistence.PreUpdate;
import javax.persistence.Version;
import play.db.ebean.Model;
@MappedSuperclass
public class Timestampable extends Model {
@Id
@GeneratedValue
public Long id;
@Column(name = "created_at")
public Date createdAt;
@Column(name = "updated_at")
public Date updatedAt;
@Version
public int version;
@Override
public void save() {
createdAt();
super.save();
}
@Override
public void update() {
updatedAt();
super.update();
}
@PrePersist
void createdAt() {
this.createdAt = this.updatedAt = new Date();
}
@PreUpdate
void updatedAt() {
this.updatedAt = new Date();
}
}