[webbeans-dev] conversation context lifecycle

[Dan Allen]

Gavin,

Since you reached an interlude (however brief it may be), I'd like to take
the opportunity to reconsider the conversation context lifecycle. Currently,
the spec states:

- For a JSF faces request, the context is active from the beginning of the
apply request values phase until the response is complete.
- For a JSF non-faces request, the context is active during the render
response phase.

I feel that these boundaries are two narrow. I'll focus first on the faces
request. In Seam, it's necessary to delay resuming the conversation until
the apply request values phase because the conversation id is stored in the
view root. At one time, the conversation context was even stored in the view
root, making it even more imperative. But we get a chance to start fresh.

There are three factors that call for the boundaries to be extended:

- As of JSF 2.0, parts of the component tree is visited in the restore view
phase, which happens to resolve value expressions bound to UIData
components. This triggers a scope not active exception if a
conversation-scoped bean is hit.
- JSF 2.0 gives us far greater flexibility to control inbound and outbound
requests. So it's no longer necessary to store the id in the view root. The
query string would be sufficient (I've already modified Web Beans to
prototype this)
- Servlets on subsequent requests may want to participate in the
conversation (and perhaps even servlet filters)

For all of these reasons, I'd like the conversation lifecycle to wrap the
entire JSF lifecycle and i'd like the conversation id to be propagated using
a query string parameter since that's the most universal way of propagating
state. As a result, custom servlets can read this value and restore the
conversation as needed. It's really inconvenient for the conversation id to
be hidden away into the component tree, aside from being problematic in JSF
2.0.

Please reconsider. Thanks.

-Dan

-- 
Dan Allen
Senior Software Engineer, Red Hat | Author of Seam in Action

http://mojavelinux.com
http://mojavelinux.com/seaminaction
http://in.relation.to/Bloggers/Dan

NOTE: While I make a strong effort to keep up with my email on a daily
basis, personal or other work matters can sometimes keep me away
from my email. If you contact me, but don't hear back for more than a week,
it is very likely that I am excessively backlogged or the message was
caught in the spam filters.  Please don't hesitate to resend a message if
you feel that it did not reach my attention.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/weld-dev/attachments/20090529/591d710d/attachment.html