I'm having some problems with inheritance and the @PrePersist annotation.
My source code looks like the following:
_the 'base' class with the annotated updateDates() method:
@javax.persistence.Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Base implements Serializable{
...
@Id
@GeneratedValue
protected Long id;
...
@Column(nullable=false)
@Temporal(TemporalType.TIMESTAMP)
private Date creationDate;
@Column(nullable=false)
@Temporal(TemporalType.TIMESTAMP)
private Date lastModificationDate;
...
public Date getCreationDate() {
return creationDate;
}
public void setCreationDate(Date creationDate) {
this.creationDate = creationDate;
}
public Date getLastModificationDate() {
return lastModificationDate;
}
public void setLastModificationDate(Date lastModificationDate) {
this.lastModificationDate = lastModificationDate;
}
...
@PrePersist
protected void updateDates() {
if (creationDate == null) {
creationDate = new Date();
}
lastModificationDate = new Date();
}
}
_ now the 'Child' class that should inherit all methods "and annotations" from the base class:
@javax.persistence.Entity
@NamedQueries({
@NamedQuery(name=Sensor.QUERY_FIND_ALL, query="SELECT s FROM Sensor s")
})
public class Sensor extends Entity {
...
// additional attributes
@Column(nullable=false)
protected String value;
...
// additional getters, setters
...
}
If I store/persist instances of the Base class to the database, everything works fine. The dates are getting updated.
But now, if I want to persist a child instance, the database throws the following exception:
MySQLIntegrityConstraintViolationException: Column 'CREATIONDATE' cannot be null
So, in my opinion, this is caused because in Child the method "@PrePersist protected void updateDates()" is not called/invoked before persisting the instances to the database.
What is wrong with my code?
