us.opulo.p.hibernate.SessionProvider.java Source code

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Here is the source code for us.opulo.p.hibernate.SessionProvider.java

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/**
 * This file is a component of the p.opulo.us project.
 *
 * Copyright (c) 2013 Jason Campos <jcampos8782@gmail.com>, Shaun Guth, Ash Islam
 * All Rights Reserved.
 *
 * This software is licensed under The MIT License (MIT)
 * http://opensource.org/licenses/MIT
 */
package us.opulo.p.hibernate;

import javax.inject.Inject;
import javax.inject.Singleton;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

import us.opulo.p.dao.HEntity;

import com.google.inject.Provider;

/**
 * Singleton provider for the hibernate connection pool. Classes implementing 
 * <code>HibernateSession</code> should inject an instance of this provider 
 * and invoke {@link #get()} to obtain the proper Session. 
 * 
 * @author Jason Campos
 */
@Singleton
public class SessionProvider implements Provider<Session> {

    private final SessionFactory sessionFactory;

    /**
     * Initializes a SessionFactory configured using the argument config. 
     * Invocations of {@link #get()} will serve from the this SessionFactory.
     *  
     * @param config The HibernateConfig used for establishing the database connection.
     */
    @Inject
    public SessionProvider(HibernateConfig config) {
        this.sessionFactory = initializeSessionFactory(config);
    }

    @Override
    public Session get() {
        Session session = SessionManager.get();
        if (session == null) {
            session = sessionFactory.openSession();
            SessionManager.set(session);
        }
        return session;
    }

    /*
     * (non-Javadoc)
     * Initializes the hibernate connection and sets the session property
     */
    private SessionFactory initializeSessionFactory(HibernateConfig config) {
        Configuration conf = new Configuration();
        conf.setProperties(config.getProperties());

        for (Class<? extends HEntity> entityClass : config.getClasses()) {
            conf.addAnnotatedClass(entityClass);
        }

        return conf.buildSessionFactory();
    }
}