Re: [jsr-314-open] [AjaxBehaviorEventAttribute] why must it be a literal?
Am Donnerstag, den 27.08.2009, 09:38 -0400 schrieb Andy Schwartz:
Hi Ed -
Ed Burns wrote:
> Which begs the question:
see: http://begthequestion.info/
> do we need to re-introduce immediate evaluation
> for EL expressions? In other words, do we bring back $?
>
Andy wrote:
I don't believe that this is necessary. Facelets of course does
not
support the concept of "immediate" expressions - ie. the Facelets engine
itself does not evaluate EL expressions. I don't believe that we want
to change this.
the Facelets-Taghandler-API actually does support immediate evaluation
of tag-attributes. See javadoc of:
javax.faces.view.facelets.TagAttribute.getObject()
What Facelets doesn't support is recognising '$' as indicator for
immediate evaluation (and making use of it in ComponentHandler-class).
Instead, we should simply follow the pattern that is
already used by other tags that evaluate EL expressions during
tag/handler execution, such as the JSTL tags. That is, we should allow
the Facelets engine to create a (deferred) ValueExpression that happens
to be evaluated by the Behavior handler when the handler is applied,
similar to the way the c:forEach "items" attribute is handled today.
I'm in favor to support '$' for immediate-evaluation (for any
attribute). It allows the page-author to indicate that an attributes
value is not intendet to change during the lifetime of that view. (Which
saves quite a number of redundant re-evaluations of EL-Expressions)
- Norbert
Andy
> Ed
>
>