com.siemens.scr.avt.ad.util.HibernateUtil.java Source code

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Here is the source code for com.siemens.scr.avt.ad.util.HibernateUtil.java

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/*
Copyright (c) 2010, Siemens Corporate Research a Division of Siemens Corporation 
All rights reserved.
    
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
    
  http://www.apache.org/licenses/LICENSE-2.0
    
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package com.siemens.scr.avt.ad.util;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.sql.SQLException;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;

/**
 * Hibernate utilities.
 * 
 * <p>
 * I first try to load a file named connection.properties from current context directory. If not found, the root directory ("/") is searched.
 * Finally, I try to load the connection properties from the system properties.
 * </p>
 * 
 * @author Xiang Li
 *
 */
public class HibernateUtil {
    private static Logger logger = Logger.getLogger(HibernateUtil.class);
    private static Configuration config = new Configuration();
    private static SessionFactory sessionFactory;
    public static final String CONNECTION_PROP_FILE = "connection.properties";
    public static final String URL = "hibernate.connection.url";
    public static final String USER = "hibernate.connection.username";
    public static final String PWD = "hibernate.connection.password";
    public static final String[] CONNECTION_KEYS = new String[] { URL, USER, PWD };

    static {
        try {
            Properties connectionProp = loadConnectionProperties();

            config.configure();
            config.addProperties(connectionProp);
            sessionFactory = config.buildSessionFactory();
        } catch (Throwable t) {
            throw new ExceptionInInitializerError(t);
        }
    }

    private static Properties loadConnectionProperties() {
        Properties connectionProp = new Properties();
        InputStream inStream = null;
        try {
            inStream = ClassLoader.getSystemClassLoader().getResourceAsStream(CONNECTION_PROP_FILE);
            if (inStream == null)
                inStream = new FileInputStream(CONNECTION_PROP_FILE); // current directory
        } catch (IOException e) {
            if (inStream == null) {
                inStream = HibernateUtil.class.getResourceAsStream("/" + CONNECTION_PROP_FILE);
            }
        } finally {
            if (inStream != null) {
                try {
                    connectionProp.load(inStream);
                    inStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            } else {
                logger.debug("try loading from system properties");
                for (String key : CONNECTION_KEYS) {
                    String value = System.getProperty(key);
                    if (value != null) {
                        connectionProp.put(key, value);
                    }
                }
            }
        }

        return connectionProp;
    }

    public static Configuration getConfiguration() {
        return config;
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static void shutdown() {
        getSessionFactory().close();
    }

    public static void save(Object obj) {
        Session session = getSessionFactory().openSession();
        save(obj, session);
        session.close();
    }

    public static void saveOrUpdate(Object obj, Session session) {
        try {
            Transaction tx = session.beginTransaction();
            session.saveOrUpdate(obj);
            tx.commit();
        } catch (HibernateException e) {
            Throwable t = e.getCause();
            if (t instanceof SQLException) {
                SQLException exp = (SQLException) t;
                while (exp != null) {
                    exp.printStackTrace();
                    exp = exp.getNextException();
                }
            }
        }
    }

    public static void save(Object obj, Session session) {
        Transaction tx = session.beginTransaction();
        session.saveOrUpdate(obj);
        tx.commit();
    }

    public static Object load(Class<?> clazz, Serializable id) {
        Session session = getSessionFactory().openSession();

        Object obj = load(clazz, id, session);

        session.close();

        return obj;
    }

    public static Object load(Class<?> clazz, Serializable id, Session session) {

        Transaction tx = session.beginTransaction();

        Object obj = session.get(clazz, id);

        tx.commit();

        return obj;
    }

    public static void update(Object obj, Session session) {
        Transaction tx = session.beginTransaction();
        session.update(obj);
        tx.commit();
    }

    public static void delete(String id) {
        Session session = getSessionFactory().openSession();

        session.delete(id);

        session.close();
    }

    public static void delete(Object obj, Session session) {
        Transaction tx = session.beginTransaction();
        session.delete(obj);
        tx.commit();
    }

    //Add session to Threadlocal
    public static final ThreadLocal session = new ThreadLocal();

    public static Session currentSession() throws HibernateException {
        Session s = (Session) session.get();

        if (s == null) {
            s = sessionFactory.openSession();
            session.set(s);
        }
        return s;
    }

    public static void closeSession() throws HibernateException {
        //Get local variable, cast it to Session type
        Session s = (Session) session.get();
        session.set(null);
        if (s != null)
            s.close();
    }

    public static void main(String[] args) {
        Configuration cfg = new Configuration().configure();
        SchemaExport schemaExport = new SchemaExport(cfg);
        schemaExport.setDelimiter(";");
        schemaExport.setFormat(true);
        schemaExport.setOutputFile("createSchema.sql");
        schemaExport.create(true, false);
    }

}