package ejava.examples.txagent.ejb;
   
   import java.rmi.RemoteException;
   import java.util.Date;
   
   import javax.annotation.PostConstruct;
   import javax.annotation.PreDestroy;
   import javax.annotation.Resource;
   import javax.ejb.EJB;
  import javax.ejb.EJBException;
  import javax.ejb.Remove;
  import javax.ejb.SessionContext;
  import javax.ejb.SessionSynchronization;
  import javax.ejb.Stateful;
  import javax.ejb.TransactionAttribute;
  import javax.ejb.TransactionAttributeType;
  import javax.persistence.EntityManager;
  import javax.persistence.PersistenceContext;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import ejava.examples.txagent.bl.AgentReservationException;
  import ejava.examples.txagent.bl.AgentReservationSession;
  import ejava.examples.txagent.blimpl.AgentSessionImpl;
  import ejava.examples.txagent.bo.Booking;
  import ejava.examples.txagent.dao.BookingDAO;
  import ejava.examples.txagent.jpa.JPABookingDAO;
  import ejava.examples.txhotel.bo.Person;
  import ejava.examples.txhotel.ejb.HotelReservationSessionRemote;
  
  /**
   * This class provides an example of a Stateful session bean that will try to
   * coordinate its local transaction with the tranaction of a remote session
   * bean. The actual configuration may not really proove anything since the
   * two applications will probably be deployed to the same server. We would
   * need to break them apart into separate servers and separate server 
   * implementations to show anything really significant.<p/>
   * 
   * Note too that this session bean declares its transaction properties using
   * class annotations. By default, this stateful session bean runs without
   * a tranaction while caching reservations for the user. A transaction is 
   * required only for the commit() call, which also signals the removal of
   * this bean instance.<p/>
   * 
   * The bean also implements the javax.ejb.SessionSynchronization interface.
   * This allows it to be called at the start and end of a transaction so that
   * it has a chance to update its cached values appropriately. This bean,
   * however, just prints some debug.
   */
  @Stateful
  @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
  public class AgentReservationSessionEJB
      implements AgentReservationSessionLocal, AgentReservationSessionRemote,
      SessionSynchronization {
      private static final Logger log = LoggerFactory.getLogger(AgentReservationSessionEJB.class);
      
      @Resource
      private SessionContext ctx;
      
      @PersistenceContext(unitName="txagent")
      private EntityManager em;
      
      @EJB(name="ejb/HotelReservationSession")
      private HotelReservationSessionRemote reservationSession;
  
      private AgentReservationSession agentSession;
      
      /**
       * This method is called immediately after dependency injection and 
       * before any business method because of the @PostConstruct annotation. 
       * It provides a chance to do any manual construction of the overall bean. 
       * In this case, we need to instantiate out business logic implementation, 
       * provide it a DAO, and register the EntityManager for the DAO(s) to use.
       */
      @PostConstruct
      public void init() {
          log.info("*** AgentReservationSessionEJB ***");
          
          //these objects were injected using only annotations within class
          log.debug("ctx=" + ctx);
          log.debug("em=" + em);
          //this object was injected using a ejb-ref in ejb-jar.xml
          log.debug("reservationSession=" + reservationSession);
          
          BookingDAO dao = new JPABookingDAO();
          ((JPABookingDAO)dao).setEntityManager(em);
          agentSession = new AgentSessionImpl();
          ((AgentSessionImpl)agentSession).setBookingDAO(dao);
          ((AgentSessionImpl)agentSession).setReservationist(reservationSession);
      }
      
      /**
       * This method should be called when the bean is destroyed because of 
       * the @PreDestory annotation.
       */
      @PreDestroy
      public void closing() {
          log.info("*** AgentReservationSessionEJB closing ***");
     }
 
     public void createBooking() throws AgentReservationException {
         agentSession.createBooking();        
     }       
 
     public void addReservation(Person person, Date startDate, Date endDate) 
         throws AgentReservationException {
         agentSession.addReservation(person, startDate, endDate);        
     }
 
     public void cancelBooking() throws AgentReservationException {
         agentSession.cancelBooking();        
     }
     
     /**
      * This method implements the big-bang. All information, up to this
      * point is being cached in the business logic instance and remote
      * hotel reservation session; all owned by this specific instance.
      * This method causes a transaction to be started, the remote reservations
      * to be commited by the hotel, and the booking to be stored locally
      * with references to the reservations. If it all works; all should be
      * stored. If something fails (e.g., an invalid reservation date), then
      * nothing will be saved.
      */
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public Booking commit() throws AgentReservationException {
         return agentSession.commit();
     }
     
     @Remove(retainIfException=false)
     public void close() {
 	    log.info("*** AgentReservationSessionEJB close ***");
 	    agentSession.close();
 	}
     
     /**
      * This method is called at the beginning of a transaction because of
      * the implements SessionSynchronization interface.
      */
     public void afterBegin()  {
         log.debug("*** Transaction Started ***");        
     }
     /**
      * This method is called just before the transaction has committed to 
      * give the bean a chance to complain.
      */
     public void beforeCompletion() throws EJBException, RemoteException {
         log.debug("*** Transaction about to complete, rollback:" + 
                 ctx.getRollbackOnly() + " ***");
     }       
     /**
      * This method is called just after the transaction has committed to 
      * tell us what happened.
      */
     public void afterCompletion(boolean status)  {
         log.debug("*** Transaction Completed:" + status + " ***");        
     }
 }