June 2004
Intermediate to advanced
792 pages
23h 17m
English
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JMS-Based Message-Driven Beans
Message-driven beans (MDBs) are stateless, server-side, transaction-aware components for processing asynchronous messages delivered via the Java Message Service. While a message-driven bean is responsible for processing messages, its container manages the component’s environment, including transactions, security, resources, concurrency, and message acknowledgment. It’s particularly important to note that the container manages concurrency. The thread-safety provided by the container gives MDBs a significant advantage over traditional JMS clients, which must be custom-built to manage resources, transactions, and security in a multithreaded environment. An MDB can process hundreds of JMS messages concurrently because numerous instances of the MDB can execute concurrently in the container.
A message-driven bean is a complete enterprise bean, just like a session or entity bean, but there are some important differences. While a message-driven bean has a bean class and EJB deployment descriptor, it does not have EJB object or home interfaces. These interfaces are absent because the message-driven bean is not accessible via the Java RMI API; it responds only to asynchronous messages.
The ReservationProcessor EJB
The ReservationProcessor EJB is a message-driven bean that receives JMS messages notifying it of new reservations. The ReservationProcessor EJB is an automated version of the TravelAgent EJB that processes reservations sent via JMS. These messages ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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