Ndtyjky

https://vladmihalcea.com/how-to-implement-a-custom-string-based-sequence-identifier-generator-with-hibernate/

i tried to this for a field that is not primary key.

Also same solution for here:
How to implement IdentifierGenerator with PREFIX and separate Sequence for each entity

But even it does not go to Java method when i run the program. It saves as null.

And i cant see the log that i put inside my class. There is no log for my class.

I copied from that blog but my code is:

public class StringSequenceIdentifier

        implements IdentifierGenerator, Configurable {



    public static final String SEQUENCE_PREFIX = "sequence_prefix";



    private String sequencePrefix;



    private String sequenceCallSyntax;



    @Override

    public void configure(

            Type type, Properties params, ServiceRegistry serviceRegistry)

            throws MappingException {

        System.out.println("xxx");

        final JdbcEnvironment jdbcEnvironment =

                serviceRegistry.getService(JdbcEnvironment.class);

        final Dialect dialect = jdbcEnvironment.getDialect();



        final ConfigurationService configurationService =

                serviceRegistry.getService(ConfigurationService.class);

        String globalEntityIdentifierPrefix =

                configurationService.getSetting( "entity.identifier.prefix", String.class, "SEQ_" );



        sequencePrefix = ConfigurationHelper.getString(

                SEQUENCE_PREFIX,

                params,

                globalEntityIdentifierPrefix);



        final String sequencePerEntitySuffix = ConfigurationHelper.getString(

                SequenceStyleGenerator.CONFIG_SEQUENCE_PER_ENTITY_SUFFIX,

                params,

                SequenceStyleGenerator.DEF_SEQUENCE_SUFFIX);



        final String defaultSequenceName = ConfigurationHelper.getBoolean(

                SequenceStyleGenerator.CONFIG_PREFER_SEQUENCE_PER_ENTITY,

                params,

                false)

                ? params.getProperty(JPA_ENTITY_NAME) + sequencePerEntitySuffix

                : SequenceStyleGenerator.DEF_SEQUENCE_NAME;



        sequenceCallSyntax = dialect.getSequenceNextValString(

                ConfigurationHelper.getString(

                        SequenceStyleGenerator.SEQUENCE_PARAM,

                        params,

                        defaultSequenceName));

    }



    @Override

    public Serializable generate(SharedSessionContractImplementor session, Object obj) {

        System.out.println("xxx");

        if (obj instanceof Identifiable) {

            Identifiable identifiable = (Identifiable) obj;

            Serializable id = identifiable.getId();

            if (id != null) {

                return id;

            }

        }

        long seqValue = ((Number) Session.class.cast(session)

                .createSQLQuery(sequenceCallSyntax)

                .uniqueResult()).longValue();



        return sequencePrefix + String.format("%011d%s", 0 ,seqValue);

    }

}

That is in my domain:

@GenericGenerator(

        name = "assigned-sequence",

        strategy = "xxxxxx.StringSequenceIdentifier",

        parameters = {

                @org.hibernate.annotations.Parameter(

                        name = "sequence_name", value = "hibernate_sequence"),

                @org.hibernate.annotations.Parameter(

                        name = "sequence_prefix", value = "CTC_"),

        }

)

@GeneratedValue(generator = "assigned-sequence", strategy = GenerationType.SEQUENCE)

private String referenceCode;

WHAT I WANT IS
I need a unique field, which is not primary. So, i decided that incrementing is best solution because otherwise, i have to check for each created random if it exists in database (i also open suggestions for this).

It will be around 5-6 characters and alphanumeric.

I want to make JPA increment this but it seems i cant do it.

This is very similar to Hibernate JPA Sequence (non-Id) but I don't think it's an exact duplicate. Yet the answers seem to apply and they seem to suggest the following strategies:

1. Make the field to be generated a reference to an entity with the only purpose that the field now becomes an ID and can get generated by the usual strategies. https://stackoverflow.com/a/536102/66686




2. Use @PrePersist to fill the field before it gets persisted. https://stackoverflow.com/a/35888326/66686




3. Make it @Generated and generate the value in the database using a trigger or similar. https://stackoverflow.com/a/283603/66686