10 tips on how to prevent business value risk
One category of risk that project teams need to ensure they address is business value failure – delivering a product that fails to provide value for the business investor.
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Posted by Scott Delap on Apr 02, 2007
- No concurrency, the default, and currently supported behavior: the bean does not support concurrent clients. The container is permitted to throw a ConcurrentAccessException if two requests arrive simultaneously.
- Bean-managed concurrency: the bean supports concurrent access by multiple threads, and is responsible for managing access to volatile data structures.
- Container-managed concurrency: the bean supports concurrent clients, and the container is responsible for ensuring that concurrent threads are serialized before entering the bean implementation.
The second item Gavin proposes is Lightweight asynchronicity. He argues that the current options of JMS and EJB timers are not enough. In addition he advocates more than one @Timeout method per bean and enhanced scheduling options. The third item mentioned is stateful web service endpoints:
...Currently, only stateless session beans may function as web service endpoints. With some integration with WS-Contexts or WS-Addessing (or whatever WS-blahblah is appropriate), we would be able to support a stateful session bean that acts as a web service endpoint. I don't know exactly what this would look like yet, but we are trialing some stuff in Seam/WS that is probably relevant...
Gavin rounds out his wish-list with an optional business interface for EJB's, Simplified JMS/JavaMail, Enhanced Logging injection, EJB meta-annotations. He argues in respect to an optional business interface:
Currently, EJB mandates that all session beans have some @Local or @Remote interface. This was not an unreasonable requirement when session beans were understood to exist in a business tier, with a well-defined API sitting between the business logic and the client. ... Especially in an environment like Seam, where the only client of a bean might be a JSF page with EL expressions, the interface looks totally redundant! ... The interface should be optional, and when it is missing, the public methods of the bean class should be taken as the business methods of the session bean...
Howard Lewis Ship and others have suggested improvements to the Servlet API:
tapestryjava.blogspot.com/2004/12/servlet-mappi...
tapestryjava.blogspot.com/2006/01/servlet-25-wh...
weblogs.java.net/blog/gmurray71/archive/2005/07...
www.bileblog.org/?p=226
Gavin is always insighted.
Some quotes from Gavin's original post:
A lot of these items have come out of our experience with Seam...
Especially in an environment like Seam, where the only client of a bean might be a JSF page with EL expressions, the interface looks totally redundant!
Currently, it is possible to inject a Topic or Queue using @Resource, but of course what I'm really interested in is QueueSender or TopicPublisher. This is easy to fix - indeed, we already fixed it in Seam.
(Just like it is in Seam.)
For example, you might have several Seam components with the following annotations:
...
Yes, we hope Web Beans JSR-299 (inspired from JBoss Seam) will be included into Java EE 6, and to do that a few other spec has to be tuned up. Nothing wrong with that :-)
"Sounds like a wishlist to make JBoss Seam a Java EE 6 standard"
Actually the main effort to introduce (some of) the ideas in Seam into the EE 6 spec is the Web Beans spec (JSR-299). We are working in close collaboration with Sun, Google, Oracle, Apache and others on this effort. The spec will be influenced by Seam, Guice, Shale, ADF and anything else we happen to find interesting :-)
The things I'm talking about in these posts are stuff that is useful and interesting even if you don't use Web Beans.
Cheers
One category of risk that project teams need to ensure they address is business value failure – delivering a product that fails to provide value for the business investor.
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