package cn.com.tarena.ecport.common.util;

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

/**
 * <pre>
 * Hibernate的工具類
 * 通過此類可以方便地使用Hibernate來管理持久層
 * </pre>
 * 
 * @author zhouyu 2008-1-16
 */
public class HibernateUtil {
	
	/**
	 * Hibernate的sessionFactory
	 * 通過sessionFactory可以創建Hibernate的session
	 */
	private static final SessionFactory sessionFactory;

	static {
		try {
			// Create the SessionFactory from hibernate.cfg.xml
			sessionFactory = new Configuration().configure()
					.buildSessionFactory();
		} catch (Throwable ex) {
			// Make sure you log the exception, as it might be swallowed
			System.err.println("Initial SessionFactory creation failed." + ex);
			throw new ExceptionInInitializerError(ex);
		}
	}

	/**
	 * 返回Hibernate的sessionFactory
	 * @return sessionFactory
	 */
	public static SessionFactory getSessionFactory() {
		return sessionFactory;
	}
	
	/**
	 * <pre>
	 * 獲得“當前”Hibernate的Session
	 * “當前”的含義可根據Hibernate配置文件中的
	 * hibernate.current_session_context_class來
	 * 配置，詳細請參考Hibernate文檔
	 * </pre>
	 * @return “當前”Hibernate的Session
	 */
	public static Session getCurrentSession(){
		return HibernateUtil.getSessionFactory().getCurrentSession();
	}
	
}