com.liusoft.util.db.Hibernate.java Source code

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Here is the source code for com.liusoft.util.db.Hibernate.java

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/*
 *  Hibernate.java
 *  
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Library General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *  
 *  Author: Winter Lau
 *  http://dlog4j.sourceforge.net
 */
package com.liusoft.util.db;

import java.io.File;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

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

/**
 * Hibernate??
 * @author liudong
 */
public class Hibernate {

    private final static Log log = LogFactory.getLog(Hibernate.class);

    private String hibernate_cfg;
    private SessionFactory sessionFactory;
    private ThreadLocal sessions;
    private ThreadLocal transactions;

    /**
     * Initialize the hibernate environment
     * @param hibernate_cfg
     * @throws MalformedURLException 
     */
    public final static Hibernate init(String hibernate_cfg) {
        return new Hibernate(hibernate_cfg);
    }

    /**
     * ???Hibernate
     * @param cfg_path
     */
    private Hibernate(String cfg_path) {
        sessions = new ThreadLocal();
        transactions = new ThreadLocal();
        Configuration cfg = new Configuration().configure(new File(cfg_path));
        sessionFactory = cfg.buildSessionFactory();
        this.hibernate_cfg = cfg_path;
    }

    /**
     * Hibernate?
     * @return
     */
    public String getHibernateConfig() {
        return hibernate_cfg;
    }

    /**
     * Get a instance of hibernate's session
     * @return
     * @throws HibernateException
     */
    public Session getSession() {
        if (sessions == null)
            return null;

        Session ssn = (Session) sessions.get();
        if (ssn == null) {
            ssn = sessionFactory.openSession();
            sessions.set(ssn);
        }

        return ssn;
    }

    /**
     * Closes the Session local to the thread.
     */
    public void closeSession() {
        if (sessions == null)
            return;
        // Would be written as a no-op in an EJB container with CMT
        Session ssn = (Session) sessions.get();
        if (ssn == null)
            return;
        else if (ssn.isOpen())
            ssn.close();

        sessions.set(null);
    }

    /**
     * Start a new database transaction.
     */
    public void beginTransaction() {
        if (transactions == null)
            return;
        // Would be written as a no-op in an EJB container with CMT
        Transaction tx = (Transaction) transactions.get();
        if (tx == null || tx.wasCommitted() || tx.wasRolledBack()) {
            Session ssn = (Session) sessions.get();
            if (ssn == null) {
                ssn = getSession();
                tx = ssn.beginTransaction();
                transactions.set(tx);
            } else if (ssn != null) {
                tx = ssn.beginTransaction();
                transactions.set(tx);
            }
        } else {
            if (tx != null && log.isWarnEnabled())
                log.warn("Trying to begin a exist transaction, nothing to do.", new Exception());
        }
    }

    /**
     * Commit the database transaction.
     */
    public void commit() {
        if (transactions == null)
            return;
        // Would be written as a no-op in an EJB container with CMT
        Transaction tx = (Transaction) transactions.get();
        if (tx != null && !tx.wasCommitted() && !tx.wasRolledBack()) {
            tx.commit();
        } else {
            if (tx != null && log.isWarnEnabled())
                log.warn("Trying to commit the uncommitable transaction, nothing to do.");
        }
        if (tx != null)
            transactions.set(null);
    }

    /**
     * Rollback the database transaction.
     */
    public void rollback() {
        if (transactions == null)
            return;
        Transaction tx = (Transaction) transactions.get();
        transactions.set(null);
        if (tx != null && !tx.wasCommitted() && !tx.wasRolledBack()) {
            tx.rollback();
        } else {
            if (tx != null && log.isWarnEnabled())
                log.warn("Trying to rollback the unrollbackable transaction, nothing to do.");
        }
    }

    /**
     * Hibernate?? 
     * @see com.liusoft.dlog4j.servlet.DLOG_ActionServlet#destroy()
     */
    public void destroy() {
        if (sessionFactory != null) {
            sessionFactory.close();
            sessionFactory = null;
        }
        sessions = null;
        transactions = null;
        if (log.isWarnEnabled())
            log.warn("Hibernate(" + hibernate_cfg + ") was destroy successfully, all of sessions were closed.");
    }

}