Web Beans Sneak Preview

In case you didn't notice, Gavin King is offering a sneak preview of the Web Beans spec (JSR 299) so far in part 1, part 2, part 3 and part 4... It's been a whole day since his last post, so it appears like now is a good time to put out some thoughts... These are in no particular, but will hopefully serve to continue the conversation to make the eventual spec as useful as possible...

• Web Beans is not just about the web, as many people have already commented (including Gavin)... while I don't necessarily need it to be brought to JSE, I believe a name change is in order...
  
• If Web Beans becomes a generic Dependency Injection mechanism, then we would be left with at least three distinct DI systems in JEE -- the Web Beans DI, the @EJB/@Resource DI from JEE 5, and the Managed Bean mechanism from JSF... something will need to be done to address this (please don't say 'Unified DI', a la 'Unified EL' :) )...
• The @In annotation clearly comes from Seam, but there might be something more appropriate here -- in Seam, there is also an @Out annotation, representing 'outjection'... So far, Gavin hasn't given us a hint of whether this will be around in Web Beans, but if not, then I think @In should become something like @Inject, @Bean, @Component, etc
• The Guice influence appears to have replaced the String-based naming in Seam (i.e. -- @Name("myBean") ) with annotations (@MyBean)... while this requires a little more code, it seems to be a good call -- it should help prevent things like typo's in the Strings causing NullPointerExceptions at Runtime...
• Very flexible -- follows the JEE5 pattern of defining a default configuration with annotations, but allowing it to be overridden or changed with an XML configuration... alternately, the XML configuration could be used as a central configuration file, as in Spring...
• The various Component Types could be hugely useful for having multiple configurations for a single application, but I would like to see more ways of defining your components -- for example, I like to be able to keep my system configurations in the app server itself, so when I deploy an EAR from test to staging to production, I can simply copy an EAR that has passed QA -- if I have to change the web-beans.xml file, I can't do this (unless there is perhaps a default that you could configure in your server)
• I love the scopes, but Gavin mentions that the @ConversionScoped will be available from JSF managed beans, while request, session and application will be available from Servlets -- what about JSF makes it the only thing that is appropriate for the conversation scope? Any reason it couldn't be available to Servlets-based frameworks like Struts, etc.?
• Could we reduce some of the annotation chatter with something like @In (scope=ConversationScoped, new=true)? Hmm... actually that ends up with more chatter -- perhaps not :)
  

That's enough for now... So far all I can say is "Great work guys!"... oh, and keep the previews coming!

M

Did Guice beat Sprint to the punch?

There's been a lot of talk over the past few years that perhaps Interface 21 should push to formally make the Spring Framework a part of the JEE specs -- it seemed like it might be possible with Rod Johnson officially declaring his support for JEE 6... well it looks like "Crazy" Bob Lee and the team behind Guice may have found a back door to get themselves into the party first -- according to a new series of articles about the upcoming Web Beans, the new spec is actually influenced by a combination of Seam and Guice, rather than just Seam as previous reports had speculated...

This is not to say that Guice and Spring cover the same ground -- Guice is strictly a product that supports dependency injection, while Spring does that and much more, but I find these articles interesting in that Google has apparently taken the JBoss approach to supporting the JCP -- that is, create an independent product to fill a whole in the JEE specs, and then use the JCP to make that product into a spec itself (take a look at the JPA for a previous example)...

I personally think it's a very smart approach -- while it will perhaps create an opening for competitors to get into the market (more applicable when considering Hibernate and Seam than with Guice, admittedly), it opens up a clear opportunity to provide the first spec-compliant implementation (thus getting early adopters), and gives them a great opportunity to build and enhance their product while the competition is catching up (keeping the early adopters :) )...

We'll see where this goes, but so far it looks like an interesting spec -- I see some potential for overlap between some other specs, but that may not be a bad thing...

M