Enterprise JavaBeans, Third Edition

Chapter 14. Transactions

ACID Transactions

To understand how transactions work, we will revisit the TravelAgent EJB, a stateful session bean that encapsulates the process of making a cruise reservation for a customer.

In EJB 2.0, the TravelAgent EJB’s bookPassage() method looks like this:

public TicketDO bookPassage(CreditCardDO card, double price)
    throws IncompleteConversationalState {
                   
    if (customer == null || cruise == null || cabin == null) {
        throw new IncompleteConversationalState();
    }
    try {
        ReservationHomeLocal resHome = (ReservationHomeLocal)
            jndiContext.lookup("java:comp/env/ejb/ReservationHomeLocal");
        ReservationLocal reservation =
            resHome.create(customer, cruise, cabin, price);
        Object ref = jndiContext.lookup
            ("java:comp/env/ejb/ProcessPaymentHomeRemote");
        ProcessPaymentHomeRemote ppHome = (ProcessPaymentHomeRemote)
            PortableRemoteObject.narrow(ref, ProcessPaymentHomeRemote.class);
        ProcessPaymentRemote process = ppHome.create();
        process.byCredit(customer, card, price);

        TicketDO ticket = new TicketDO(customer,cruise,cabin,price);

        return ticket;
    } catch(Exception e) {
        throw new EJBException(e);
    }
}

In EJB 1.1, the bookPassage() method looks like this:

public TicketDO bookPassage(CreditCardDO card, double price) throws IncompleteConversationalState { if (customer == null || cruise == null || cabin == null) { throw new IncompleteConversationalState(); } try { ReservationHomeRemote resHome = (ReservationHomeRemote) getHome("ReservationHomeRemote", ReservationHomeRemote.class); ReservationRemote ...