package org.lsst.ccs.config.dao.hibernate;
   
   import org.hibernate.HibernateException;
   import org.hibernate.Session;
   import org.hibernate.SessionFactory;
   import org.hibernate.cfg.Configuration;
   import org.hibernate.service.ServiceRegistry;
   import org.hibernate.service.ServiceRegistryBuilder;
   import org.lsst.ccs.config.HqlDAO;
  
  import java.util.List;
  import java.util.logging.Level;
  
  import static org.lsst.ccs.config.PackCst.CURLOG;
  
  /**
   * @author bamade
   */
  // Date: 12/03/13
  
  public class HibernateDAO extends HqlDAO {
      class SessionDelegate implements AbstractSession {
          Session session ;
  
          SessionDelegate(Session session) {
              this.session = session;
          }
  
          @Override
          public void save(Object o) throws HibernateException {
               session.save(o);
          }
  
          @Override
          public void saveOrUpdate(Object o) throws HibernateException {
              session.saveOrUpdate(o);
          }
  
          @Override
          public void delete(Object o) throws HibernateException {
              session.delete(o);
          }
  
          @Override
          public void flush() {
              session.flush();
          }
  
          @Override
          public AbstractQuery createQuery(final String s) {
              return new AbstractQuery() {
                  org.hibernate.Query query = session.createQuery(s) ;
                  @Override
                  public List list() {
                      return query.list() ;
                  }
              } ;
          }
      }
      protected SessionFactory sessionFactory;
      org.hibernate.Session session ;
      org.hibernate.Transaction currentTransaction ;
      private boolean exceptionFired ;
  
      public HibernateDAO() {
          initSession() ;
          session = openSession();
      }
  
      /*
      dangerous: method to be specialized (to get different service)
       */
      protected void initSession() {
          try {
              /**/
              Configuration configuration = new Configuration().configure() ;
              // Create the SessionFactory from standard (hibernate.cfg.xml)
              ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().
                      applySettings(configuration.getProperties()).buildServiceRegistry();
              sessionFactory = configuration.buildSessionFactory(serviceRegistry);
              /**/
              //sessionFactory = new AnnotationConfiguration().configure("hibernate.cfg.xml").buildSessionFactory();
  
  
              // config file.
          } catch (Throwable ex) {
              // Log the exception.
              CURLOG.log(Level.SEVERE, "Initial SessionFactory creation failed.", ex);
              throw new ExceptionInInitializerError(ex);
          }
      }
      public  SessionFactory getSessionFactory() {
          return sessionFactory;
      }
      @Override
      public void begin() {
          CURLOG.fine("begin transaction");
          session = getCurrentSession();
          exceptionFired = false ;
         currentTransaction = session.beginTransaction() ;
         //throw new UnsupportedOperationException("Not supported yet.");
     }
 
     @Override
     public void end() {
         // use of wasrollback not sure ...
         CURLOG.fine("end transaction");
         if(!exceptionFired) {
             session.flush();
             currentTransaction.commit() ;
             currentTransaction = null ;
         }
     }
 
     @Override
     public void fail() {
         if(currentTransaction != null) {
             currentTransaction.rollback();
         }
     }
 
     @Override
     public void fail(Throwable th) {
         CURLOG.log(Level.SEVERE,"",th);
         fail() ;
     }
 
 
     //TODO : write a "pumping" query
 
     @Override
     public void close() {
         session.close();
         sessionFactory.close();
     }
 
     protected Session getCurrentSession() {
         Session res = sessionFactory.getCurrentSession() ;
         setSession(new SessionDelegate(res));
         return res;
 
     }
 
     protected Session openSession() {
         Session res = sessionFactory.openSession() ;
         setSession(new SessionDelegate(res));
         return res;
     }
 
 }