CODEWITHSUNDEEP
javahibernateinstance
earthmover
earthmover

Reputation: 4525

What is INSTANCE in HibernateUtil?

I am new to Hibernate framework of Java. I have a code of HibernateUtil class, I didn't understand from where the INSTANCE came. It holds the onstance of HibernateUtil class, how???

The code is this...

import java.util.Properties;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

public enum HibernateUtil {

INSTANCE;   // what about this???
public static SessionFactory sessionFactory = null;

private synchronized SessionFactory initialiseSessionFactory() {

    if (sessionFactory == null) {
        Configuration config = new Configuration();

        config.addAnnotatedClass(demo1.class);
        config.addAnnotatedClass(demo2.class);
        config.configure();

        //get the properties from Hibernate configuration file
        Properties configProperties = config.getProperties();
        ServiceRegistryBuilder serviceRegisteryBuilder = new ServiceRegistryBuilder();
        ServiceRegistry serviceRegistry = serviceRegisteryBuilder.applySettings(configProperties).buildServiceRegistry();
        sessionFactory = config.buildSessionFactory(serviceRegistry);

    }
    return sessionFactory;
}

public Session getSession() {
    Session hibernateSession = null;

    if (sessionFactory == null) {
        hibernateSession = initialiseSessionFactory().openSession();

    } else {
        hibernateSession = sessionFactory.openSession();
           }
    return hibernateSession;
}
}

Upvotes: 1

Views: 640

Answers (2)

Sameer
Sameer

Reputation: 2171

An enum in Java is actually a class. One that implicitly extends java.lang.Enum. The special syntax you see at INSTANCE; is a declaration of an enum constant. This is going to be used to make an instance of your enum class which can be referred to in code.

Upvotes: 0

Maurice Perry
Maurice Perry

Reputation: 32831

HibernateUtil is implementing the singleton pattern: there can be only one instance of that class, and that instance is HibernateUtil.INSTANCE.

Upvotes: 2

Related Questions