org.smartsnip.persistence.hibernate.DBSessionFactory.java Source code

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Here is the source code for org.smartsnip.persistence.hibernate.DBSessionFactory.java

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/**
 * File: DBSessionFactory.java
 * Date: 28.04.2012
 */
package org.smartsnip.persistence.hibernate;

import org.apache.log4j.Logger;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

/**
 * @author Gerhard Aigner
 * 
 */
public class DBSessionFactory {

    private DBSessionFactory() {
        // static only class
    }

    private static SessionFactory factory = null;
    private static ServiceRegistry serviceRegistry;

    /**
     * initialize the session factory
     * 
     * @param configFile
     *            the path to the configuration file
     * @throws ExceptionInInitializerError
     */
    private static synchronized void initialize(String configFile) throws ExceptionInInitializerError {
        if (configFile == null || configFile.isEmpty()) {
            configFile = "/hibernate.cfg.xml";
        }
        if (factory == null) {
            try {
                Configuration configuration = new Configuration();
                configuration.configure(configFile);

                // add entity classes
                configuration.addAnnotatedClass(DBCategory.class);
                configuration.addAnnotatedClass(DBCode.class);
                configuration.addAnnotatedClass(DBCodeFile.class);
                configuration.addAnnotatedClass(DBComment.class);
                configuration.addAnnotatedClass(DBFavourite.class);
                configuration.addAnnotatedClass(DBLanguage.class);
                configuration.addAnnotatedClass(DBLicense.class);
                configuration.addAnnotatedClass(DBLogin.class);
                configuration.addAnnotatedClass(DBNotification.class);
                configuration.addAnnotatedClass(DBRating.class);
                configuration.addAnnotatedClass(DBSnippet.class);
                configuration.addAnnotatedClass(DBTag.class);
                configuration.addAnnotatedClass(DBUser.class);
                configuration.addAnnotatedClass(DBVote.class);
                configuration.addAnnotatedClass(DBRelTagSnippet.class);

                serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())
                        .buildServiceRegistry();
                factory = configuration.buildSessionFactory(serviceRegistry);
            } catch (Throwable ex) {
                Logger log = Logger.getLogger(DBSessionFactory.class);
                log.error("Failed to create sessionFactory object.", ex);
                throw new ExceptionInInitializerError(ex);
            }
        }
    }

    /**
     * Get a SessionFactory instance.
     * 
     * @return the factory with default configuration from the hibernate.cfg.xml
     *         file
     */
    public static SessionFactory getInstance() {
        return getInstance(null);
    }

    /**
     * Get a SessionFactory instance.
     * 
     * @param configFile
     *            the file to read the configuration from
     * @return the factory with custom configuration
     */
    public static SessionFactory getInstance(String configFile) {
        if (factory == null)
            initialize(configFile);
        return factory;
    }

    /**
     * close the session factory
     * 
     * @see org.hibernate.SessionFactory#close()
     */
    public static void closeFactory() {
        factory.close();
    }

    /**
     * Open a new session. It is recommended to handle a session by one thread.
     * 
     * @return the session
     */
    static Session open() {
        SessionFactory factory = DBSessionFactory.getInstance();
        return factory.openSession();
    }

    /**
     * close the given session
     * 
     * @param session
     */
    static void close(Session session) {
        session.close();
    }
}