package org.hibernate.ce.auction.persistence;
import org.hibernate.*;
import org.hibernate.util.PropertiesHelper;
import org.hibernate.cfg.*;
import org.apache.commons.logging.*;
/**
* Basic Hibernate helper class, handles SessionFactory, Session and Transaction.
* <p>
* Uses a static initializer to read startup options and initialize
* <tt>Configuration</tt> and <tt>SessionFactory</tt>
* <p>
* This class tries to figure out if either ThreadLocal handling of the
* <tt>Session</tt> and <tt>Transaction</tt> should be used, or if CMT is used.
* In the latter case transaction/session handling methods are disabled and the
* container does the job with Hibernate's automatic JTA binding. To keep your
* DAOs free from any of this, just call <tt>HibernateUtil.getSession()</tt> in
* the constructor of each DAO and use either client transactions/BMT or CMT
* to set transaction and session boundaries.
* <p>
* If you want to assign a global interceptor, set its fully qualified
* classname with the system (or hibernate.properties) property
* <tt>hibernateutil.interceptor</tt>. It will be loaded and instantiated
* on static initialization of HibernateUtil, and it has to have a
* no-argument constructor. You can call <tt>getInterceptor()</tt> if
* you need to provide settings before using the interceptor.
*
* @author
[email protected] */
public class HibernateUtil {
private static Log log = LogFactory.getLog(HibernateUtil.class);
private static Configuration configuration;
private static SessionFactory sessionFactory;
private static ThreadLocal threadSession = new ThreadLocal();
private static ThreadLocal threadTransaction = new ThreadLocal();
private static boolean useJNDIBinding = false;
private static boolean useThreadLocal = true;
// Create the initial SessionFactory from the default configuration files
static {
try {
// Replace with Configuration() if you don't use annotations
configuration = new AnnotationConfiguration();
// Read not only hibernate.properties, but also hibernate.cfg.xml
configuration.configure();
// Assign a global, user-defined interceptor with no-arg constructor
String interceptorName = PropertiesHelper.getString("hibernateutil.interceptor_class",
configuration.getProperties(),
null);
if (interceptorName != null) {
Class interceptorClass =
HibernateUtil.class.getClassLoader().loadClass(interceptorName);
Interceptor interceptor = (Interceptor)interceptorClass.newInstance();
configuration.setInterceptor(interceptor);
}
// Enable JNDI binding code if the SessionFactory has a name
if (configuration.getProperty(Environment.SESSION_FACTORY_NAME) != null)
useJNDIBinding = true;
// Disable ThreadLocal Session/Transaction handling if CMT is used
if ("org.hibernate.transaction.CMTTransactionFactory"
.equals( configuration.getProperty(Environment.TRANSACTION_STRATEGY) ) )
useThreadLocal = false;
if (useJNDIBinding) {
// Let Hibernate bind it to JNDI
configuration.buildSessionFactory();
} else {
// or use static variable handling
sessionFactory = configuration.buildSessionFactory();
}
} catch (Throwable ex) {
// We have to catch Throwable, otherwise we will miss
// NoClassDefFoundError and other subclasses of Error
log.error("Building SessionFactory failed.", ex);
throw new ExceptionInInitializerError(ex);
}
}
/**
* Returns the original Hibernate configuration.
*
* @return Configuration
*/
public static Configuration getConfiguration() {
return configuration;
}
/**
* Returns the SessionFactory used for this static class.
*
* @return SessionFactory
*/
public static SessionFactory getSessionFactory() {
if (useJNDIBinding) {
SessionFactory sessions = null;
try {
log.debug("Looking up SessionFactory in JNDI.");
javax.naming.Context ctx = new javax.naming.InitialContext();
String jndiName = "java:hibernate/HibernateFactory";
sessions = (SessionFactory)ctx.lookup(jndiName);
} catch (javax.naming.NamingException ex) {
throw new RuntimeException(ex);
}
return sessions;
}
if (sessionFactory == null)
throw new IllegalStateException("Hibernate has been shut down.");
return sessionFactory;
}
/**
* Closes the current SessionFactory and releases all resources.
* <p>
* The only other method that can be called on HibernateUtil
* after this one is rebuildSessionFactory(Configuration).
* Note that this method should only be used with static SessionFactory
* management, not with JNDI or any other external registry.
*/
public static void shutdown() {
log.debug("Shutting down Hibernate.");
// Close caches and connection pools
getSessionFactory().close();
// Clear static variables
configuration = null;
sessionFactory = null;
// Clear ThreadLocal variables
threadSession.set(null);
threadTransaction.set(null);
}
/**
* Rebuild the SessionFactory with the static Configuration.
* <p>
* This method also closes the old SessionFactory before, if still open.
* Note that this method should only be used with static SessionFactory
* management, not with JNDI or any other external registry.
*/
public static void rebuildSessionFactory() {
log.debug("Using current Configuration for rebuild.");
rebuildSessionFactory(configuration);
}
/**
* Rebuild the SessionFactory with the given Hibernate Configuration.
* <p>
* HibernateUtil does not configure() the given Configuration object,
* it directly calls buildSessionFactory(). This method also closes
* the old SessionFactory before, if still open.
*
* @param cfg
*/
public static void rebuildSessionFactory(Configuration cfg) {
log.debug("Rebuilding the SessionFactory from given Configuration.");
synchronized(sessionFactory) {
if (sessionFactory != null && !sessionFactory.isClosed())
sessionFactory.close();
if (useJNDIBinding)
cfg.buildSessionFactory();
else
sessionFactory = cfg.buildSessionFactory();
configuration = cfg;
}
}
/**
* Retrieves the current Session local to the thread.
* <p/>
* If no Session is open, opens a new Session for the running thread.
*
* @return Session
*/
public static Session getSession() {
if (useThreadLocal) {
Session s = (Session) threadSession.get();
if (s == null) {
log.debug("Opening new Session for this thread.");
s = getSessionFactory().openSession();
threadSession.set(s);
}
return s;
} else {
return getSessionFactory().getCurrentSession();
}
}
/**
* Closes the Session local to the thread.
*/
public static void closeSession() {
if (useThreadLocal) {
Session s = (Session) threadSession.get();
threadSession.set(null);
if (s != null && s.isOpen()) {
log.debug("Closing Session of this thread.");
s.close();
}
} else {
log.warn("Using CMT/JTA, intercepted superfluous close call.");
}
}
/**
* Start a new database transaction.
*/
public static void beginTransaction() {
if (useThreadLocal) {
Transaction tx = (Transaction) threadTransaction.get();
if (tx == null) {
log.debug("Starting new database transaction in this thread.");
tx = getSession().beginTransaction();
threadTransaction.set(tx);
}
} else {
log.warn("Using CMT/JTA, intercepted superfluous tx begin call.");
}
}
/**
* Commit the database transaction.
*/
public static void commitTransaction() {
if (useThreadLocal) {
Transaction tx = (Transaction) threadTransaction.get();
try {
if ( tx != null && !tx.wasCommitted()
&& !tx.wasRolledBack() ) {
log.debug("Committing database transaction of this thread.");
tx.commit();
}
threadTransaction.set(null);
} catch (RuntimeException ex) {
log.error(ex);
rollbackTransaction();
throw ex;
}
} else {
log.warn("Using CMT/JTA, intercepted superfluous tx commit call.");
}
}
/**
* Rollback the database transaction.
*/
public static void rollbackTransaction() {
if (useThreadLocal) {
Transaction tx = (Transaction) threadTransaction.get();
try {
threadTransaction.set(null);
if ( tx != null && !tx.wasCommitted() && !tx.wasRolledBack() ) {
log.debug("Tyring to rollback database transaction of this thread.");
tx.rollback();
log.debug("Database transaction rolled back.");
}
} catch (RuntimeException ex) {
throw new RuntimeException("Might swallow original cause, check ERROR log!", ex);
} finally {
closeSession();
}
} else {
log.warn("Using CMT/JTA, intercepted superfluous tx rollback call.");
}
}
/**
* Reconnects a Hibernate Session to the current Thread.
*
* @param session The Hibernate Session to be reconnected.
*/
public static void reconnect(Session session) {
if (useThreadLocal) {
log.debug("Reconnecting Session to this thread.");
session.reconnect();
threadSession.set(session);
} else {
log.error("Using CMT/JTA, intercepted not supported reconnect call.");
}
}
/**
* Disconnect and return Session from current Thread.
*
* @return Session the disconnected Session
*/
public static Session disconnectSession() {
if (useThreadLocal) {
Session session = getSession();
threadSession.set(null);
if (session.isConnected() && session.isOpen()) {
log.debug("Disconnecting Session from this thread.");
session.disconnect();
}
return session;
} else {
log.error("Using CMT/JTA, intercepted not supported disconnect call.");
return null;
}
}
/**
* Register a Hibernate interceptor with the current SessionFactory.
* <p>
* Every Session opened is opened with this interceptor after
* registration. Has no effect if the current Session of the
* thread is already open, effective on next close()/getSession().
* <p>
* Attention: This method effectively restarts Hibernate. If you
* need an interceptor active on static startup of HibernateUtil, set
* the <tt>hibernateutil.interceptor</tt> system property to its
* fully qualified class name.
*/
public static void registerInterceptorAndRebuild(Interceptor interceptor) {
log.debug("Setting new global Hibernate interceptor and restarting.");
configuration.setInterceptor(interceptor);
rebuildSessionFactory();
}
public static Interceptor getInterceptor() {
return configuration.getInterceptor();
}
}
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