JSTL c:if tag always test false inside JSF facelet ui:repeat tag
November 14, 2011 20:50:51 Last update: November 22, 2011 09:06:10
This facelet fragment will never print anything:
because the test condition always returns false, even though the
The same happens even when I define another variable with
What's happening? The
The solution? Use
Or use
<ui:repeat var="person" value="#{myBean.theJTeam}"> <c:if test="#{person != null}"> JSTL: #{person}<br/> </c:if> </ui:repeat>
because the test condition always returns false, even though the
person var is not null.
The same happens even when I define another variable with
ui:param:
<ui:repeat var="person" value="#{myBean.theJTeam}"> <ui:param name="aperson" value="#{person}"/> <c:if test="#{aperson != null}"> JSTL: #{aperson}<br/> </c:if> </ui:repeat>
What's happening? The
c:if test condition is evaluated before the ui:repeat tag had a chance to set the value! Both facelet ui tags and JSTL c tags are evaluated at the Render Response phase of the JSF lifecycle. But within the Render Response cycle, there are two sub-phases (so to speak): the first builds the UI element tree, the second renders the UI tree. The JSTL c:if tag is evaluated when the tree is built, but the facelet ui:repeat tag is evaluated when the UI tree is rendered. Bad design indeed. Why should a tag user know the implementation details in order to use the tags correctly?
The solution? Use
ui:fragment if you can:
<ui:repeat var="person" value="#{myBean.theJTeam}"> <ui:fragment rendered="#{person != null}"> UI Fragment: #{aperson}<br/> </ui:fragment> </ui:repeat>
Or use
c:forEach for the loop instead of ui:repeat.
