Using value binding expressions to set 'required' attribute

Question

I am trying to use a value binding expression to determine whether the value of various input control's is required or not according to where they are used and not having much luck. I wonder if anyone can shed some light on this...
The following expression works: <h:inputText id="name" required="#{true}"/> whereas <c:set var="required" value="true" scope="request"/>
<h:inputText id="name" required="#{required}"/> does not, even though the expression evaluates to true! I have tried numerous variations (requestScope.required, required == true, required ? true : false, etc.) to no avail. Interestingly, #{1 == 1} or binding to a backing bean method works, but as soon as you add a request variable it breaks.
Am I doing something wrong, is this something that JSF doesn't allow, or just a bug in the RI? Note that I don't want to vary this flag between multiple submissions of the same form, I am just trying to reuse the same JSP include to generate form controls for required and optional data on different forms to avoid a whole lot of cutting any pasting.
Any pointers gratefully received.
-- Keith Wilson

Answer 1

I had something like this happen, and here's what I concluded the problem was. Perhaps your problem is similar.
In the first non-working example you show a request-scope variable being set in the JSP page, and then use that to set the "required" attribute. But consider what happens when you submit the form. There is no longer any request-scope variable set because we have a new request and we don't go through the JSP page! (Not before validation is checked, anyhow).
So basically I concluded that the variable had to be in (say) session scope for it to work as you would like.