Is it possible to set a filed in hibernate to have a value generated whenever it is null?
This is not the primary key but business key. Basically I have a container with a barcode field. If no barcode is assigned, generate it automatically (eg, prefix + sequence number).
Is that possible or do I need to create a custom method for accessing the next sequence value?
Have a look at this: Hibernate JPA Sequence (non-Id)
The idea is to create an entity for the generated value BarCode and then use it as a property of your main entity:
@Entity
public class BarCode{
private static final String PREFIX = "PREFIX";
@Id
@GeneratedValue(...)
private Long number;
public String getBarCodeValue(){
return PREFIX + getNumber();
}
}
@Entity
public class MyEntity {
@Id ..
private Long id;
@OneToOne(...)
private BarCode barCode;
public String getBarCodeValue(){
return barCode.getBarCodeValue();
}
}
Assign the value for the barcode from the class itself. Try something like this.
int sequencenumber = generateSequence();
String barcode = prefix + sequencenumber;
I haven't tried this out. So I am not sure if this will work. Do try it out.
Also check this out: Setting default values for columns in JPA
