[jbossseam-issues] [JBoss JIRA] Commented: (JBSEAM-1733) A limitation in the expression language enhancements is not documented

[Wise Guy (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBSEAM-1733?page=comments#action_12370288 ] 
            
Wise Guy commented on JBSEAM-1733:
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I think you mean the object returned by LocaleSelector.getSupportedLocales() is not scoped. I know that and I know this will be the reason curLocale in my example cannot be evaluated after the link is clicked.

What I wanted to note is that if someone wants to have variable evaluated to a literal string and at the same time this variable should be used in a MethodBinding, these two are impossible. Maybe my example was not good. Instead of:
#{localeSelector.selectLanguage(curLocale.value)}
I should've have noted it:
#{localeSelector.selectLanguage('#{curLocale.value}')}

So that one can easily see the syntax is wrong. You cannot both evaluate #{curLocale.value} to "de" and pass #{localeSelector.selectLanguage('de')} as MethodBinding. What you should do is separately pass the variable as a request parameter (as the workaround stated). Yes, I finally agree that the workaround is the best solution.

I wanted this cleared out for the users in the reference manual. I guess the discussions made here and on the forum are already enough. If you don't want to include it there, I'm ok with that.

Sorry for taking so much attention on this issue. As I stated this was not my intention. I have great respect for your work. Please continue what you do best.

> A limitation in the expression language enhancements is not documented
> ----------------------------------------------------------------------
>
>                 Key: JBSEAM-1733
>                 URL: http://jira.jboss.com/jira/browse/JBSEAM-1733
>             Project: JBoss Seam
>          Issue Type: Task
>          Components: JSF, Documentation, EL
>            Reporter: Wise Guy
>            Priority: Minor
>
> There is a limitation in the expression language enhancements that is not documented. It would look like this:
> ---
> http://docs.jboss.com/seam/2.0.0.B1/reference/en/html/elenhancements.html
> Chapter 29. Expression language enhancements
> 29.1.2. Limitations
> 29.1.2.3. Cannot pass a variable to a MethodBinding
> You may not pass a variable to a MethodBinding, hence the following syntax is not valid:
> <ui:repeat var="curLocale" value="#{localeSelector.supportedLocales}">
>   <s:link value="#{curLocale.label}" action="#{localeSelector.selectLanguage(curLocale.value)}"/>
> </ui:repeat>
> Seam cannot evaluate "curLocale.value" in the rendering phase because it is a part of a MethodBinding. If you need to do implement the same functionality  then use the f:param tag:
> <s:link value="#{curLocale.label}" action="#{localeProvider.updateLocale()}">
>     <f:param name="l" value="#{curLocale.value}"/>
> </s:link>
> Then, having the field variable "l" injected as a @RequestParameter, you would do this:
> public void updateLocale() {
>         if (l != null && l.length() > 0) {
>             localeSelector.selectLanguage(l);
>         }
> }	
> --
> May I also point out that you should merge "29.1. Parameterized Method Bindings"  and "29.2. Parameterized Value Bindings". (2.0.0.B1/reference)
> Thank you for the attention

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