hibernate JPA: optional value generation

Question

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?

there is an option to give default value. something like default = '' Have used it for giving default date for one timestamp field. — vishnu viswanath, Mar 28 '13 at 12:46

score 1 · Answer 1 · edited May 23 '17 at 12:08

1

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();
    }
}

edited May 23 '17 at 12:08

Community

1
1

answered Mar 28 '13 at 12:55

Balázs Németh

6,222
9
45
60

I don't want to generate always. The value can be supplied from the outside and generation is only required if it is not supplied. – beginner_ Apr 04 '13 at 12:14

score 0 · Answer 2 · edited May 23 '17 at 12:31

0

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

edited May 23 '17 at 12:31

Community

1
1

answered Mar 28 '13 at 12:54

vishnu viswanath

3,794
2
36
47

hibernate JPA: optional value generation

2 Answers2