HiLo generator strategy not working

Question

I am new to hibernate. What I am trying to do is use @CollectionIdto generate an identifier for my Address class. I have used Collection interface for this. However when I use @GenericGenerator and set strategy to hilo, it throws an Exception. Here's my code:

@Entity
@Table(name = "USER_DETAILS")
public class UserDetails {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int userId;
    private String userName;

    @ElementCollection
    @JoinTable(name="USER_ADDRESS",
        joinColumns=@JoinColumn(name="USER_ID")
    )

    @GenericGenerator(name = "hilo-gen", strategy = "hilo")
    @CollectionId(columns = { @Column(name="ADDRESS_ID") }, generator = "hilo-gen", type = @Type(type="long"))
    private Collection<Address> address = new ArrayList<Address>();

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Collection<Address> getAddress() {
        return address;
    }

    public void setAddress(List<Address> address) {
        this.address = address;
    }
}

I get the following exception:

Exception in thread "main" org.hibernate.MappingException: Could not instantiate id generator [entity-name=null]
    at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.createIdentifierGenerator(DefaultIdentifierGeneratorFactory.java:121)
    at org.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:259)
    at org.hibernate.persister.collection.AbstractCollectionPersister.<init>(AbstractCollectionPersister.java:429)
    at org.hibernate.persister.collection.BasicCollectionPersister.<init>(BasicCollectionPersister.java:57)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.hibernate.persister.internal.PersisterFactoryImpl.createCollectionPersister(PersisterFactoryImpl.java:152)
    at org.hibernate.persister.internal.PersisterFactoryImpl.createCollectionPersister(PersisterFactoryImpl.java:140)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:408)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:444)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
    at com.hbt.HibernateTest.main(HibernateTest.java:35)
Caused by: java.lang.UnsupportedOperationException: Support for 'hilo' generator has been removed
    at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.getIdentifierGeneratorClass(DefaultIdentifierGeneratorFactory.java:132)
    at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.createIdentifierGenerator(DefaultIdentifierGeneratorFactory.java:112)
    ... 14 more

I am using the latest hibernate. What should I do?

Freudberg

Also I am using MySql as my database – Freudberg

Answer 1

Hilo is not supported anymore, this should work

@GenericGenerator(name="sequence-gen",strategy="sequence")

Cholera

can you explain the reason for the removal of halo – Salamander

Answer 2

If we are using mysql it would be better to use the @GenericGenerator of increment strategy.

1. sequence - This sort of strategy supports by Oracle, Postgresql.

2. increment - This sort of strategy supports by MySql.

   @ElementCollection
   @JoinTable(name="USER_ADDRESS", joinColumns=@JoinColumn(name="USER_ID"))
   @GenericGenerator(name = "increment-gen", strategy = "increment")
   @CollectionId(columns = { @Column(name="ADDRESS_ID") }, generator = "increment-gen", type = @Type(type="long"))
   private Collection<Address> listOfAddress = new ArrayList<>();
   

When I have used the sequence strategy with MySql I came across an issue where my ADDRESS_ID is not getting incremented properly.

Boy

Thanks for this information it is quit helpful, i too was getting the error but not the above one, my code refused to compile with below error- org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "drop table if exists sequence-gen" via JDBC Statement. But modifying strategy to increment resolved the issue. – Disregardful

Answer 3

The Support for 'hilo' generator has been removed. For additional information, this link gives you the deprecated list.

To overcome this, you can simply use sequence generator. This will solve your problem.

@Entity
@Table(name = "USER_DETAILS")
public class UserDetails {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int userId;
    private String userName;

    @ElementCollection
    @JoinTable(name="USER_ADDRESS",
        joinColumns=@JoinColumn(name="USER_ID")
    )

    @GenericGenerator(name = "sequence-gen", strategy = "sequence")
    @CollectionId(columns = { @Column(name="ADDRESS_ID") }, generator = "sequence-gen", type = @Type(type="long"))
    private Collection<Address> address = new ArrayList<Address>();

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Collection<Address> getAddress() {
        return address;
    }

    public void setAddress(List<Address> address) {
        this.address = address;
    }
}

Marylyn

Answer 4

FYI, MYSQL supports sequence strategy however table name should not contain hyphen '-' (which is name provided in @GenericGenerator(name) could cause DDL exception while creating sequence table in mysql.

Wanda

Answer 5

This is what works for apps on PostgreSQL. Though I have not tested it, it should work for all DBs. Note that increment-gen is used not sequence.

@ElementCollection
    @JoinTable( name = "user_address", joinColumns = @JoinColumn( name = "user_id"))
    @GenericGenerator(name="increment-gen",strategy="increment")
    @CollectionId( columns = { @Column( name ="address_id") }, generator ="increment-gen", type =@Type( type ="long"))
    private Collection<Address> listOfAddresses = new ArrayList<Address>();

Puggree

Answer 6

You must choose from one of the Hi/Lo strategy :

• SequenceHiLoGenerator : to back the Hi with a Sequence
• MultipleHiLoPerTableGenerator : to back the Hi with a Table

To be as close as your tutorial as possible, I would simply change "hilo" to "seqhilo" in your code.

Mangonel

Has there been any change in latest hibernate? Coz the tutorial I am following uses hibernate 3.0. And I am using hibernate 5.0. Does the latest version not support hilo? – Freudberg

I do not know when they made the change, but from what I know you should use one of the above strategy. To be as close as your tutorial as possible, I would simply change "hilo" into "seqhilo" – Springe

@AdityaSawant Support for 'hilo' generator has been removed – Hartfield

@Hartfield what is the reason for the removal? – Salamander

@KasunSiyambalapitiya i have no idea. But as far as i remember , they just replaced the way it's implemented or used. So you can still have the functionality , if you adjust your code properly – Hartfield

Answer 7

I would recommend you to try any of the below 2 solutions and it will fix your issue. it is as per the specification provided in Hibernate 5.2.X.

Source Of Info -https://docs.jboss.org/hibernate/orm/5.2/userguide/html_single/Hibernate_User_Guide.html

Solution 1 -

 @GenericGenerator(name = "product_generator",strategy = "org.hibernate.id.enhanced.SequenceStyleGenerator")
 @CollectionId(columns = { @Column(name="ADDRESS_ID") }, generator = "product_generator", type = @Type(type="long"))*

Solution 2 -

*@GeneratedValue(strategy = GenerationType.SEQUENCE,generator = "product_generator")
 @CollectionId(columns = { @Column(name="ADDRESS_ID") }, generator = "product_generator", type = @Type(type="long"))*

Let me know if it helps you.

Kutzenco

Can you explain what is the source of the problem and how your three lines fix it? – Nombles

The source of the problem is Aditya Sawant was trying to use Hilo strategy in hibernate. Which is deprecated in newer versions of hibernate. My 2 solution advises on how to achieve the same goal using the Generic Generator of SEQUENCE type. – Kutzenco