[jboss-user] [JBoss Seam] - Re: Evaluation of action attibute in s:link

[dmitriy.lapko]

I'm not sure it is a problem of Seam. It is a limitation of JSF EL. You cannot construct JSF EL dynamically - that is what you would like to have. You cannot have nasted EL constructions. 

I just cannot understand, how would you like to fix this limitation - it will break the logic of EL, if you can use JSF page variable to construct expression. For me the problem is in specific logic you would like to have only for action attribute - don't you want this feature for ALL EL expressions?

For example: 

  |  <s:link value="#{curLocale.label}" action="#{localeSelector.selectLanguage(curLocale.value)}"/>
  | 

If you would like to have the feature you posted in JIRA, then the parser of EL should try to check, is localeSelector also a page variable.

Or in case there is curLocale component in the session scope, what should be done?

Seam doesn't provide it's own parser of expressions, it uses standard but almost everewhere (that is cool :)).

As for me, nested EL can be another powerful feature, which can help new developers to avoid such mistakes - they will be able to construct expressions dynamically with respect to current context, like:


  |  <s:link value="#{curLocale.label}" action="#{localeSelector.selectLanguage(#{curLocale.value})}"/>
  | 

But may be it would just make the code more complicated. The decision with <f:param is more clear, you should just to know it and not to try to do what we did with you.

Hope, this topic is closed :)

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