<c:if> tag for JSF page

Question

Used to develop Portlets and JPS's, so have a dilemma.

task: display <h:dataTable> only when list isn't empty

Is it possible to provide <c:if> tag for JSF page?

Answer 1

Yes, you can add JSTL tags in your JSF pages. However, in your case, you can simply do the following:

<h:dataTable value="#{myBean.list}"... rendered="#{myBean.displayTable}">
    ...
</h:dataTable>

with the following method in myBean:

public boolean isDisplayTable() {
    return list != null && list.size() > 0;
}

You can also try that (not sure if it will work):

<!-- Idea from Colin Gislason -->
<h:dataTable value="#{myBean.list}"... rendered="#{not empty myBean.list}">
    ...
</h:dataTable>

<h:dataTable value="#{myBean.list}"... rendered="#{not myBean.list.empty}">
    ...
</h:dataTable>

Note that you can use the ! instead of the not keyword in the EL expressions (see a guide here about EL expressions), which results in rendered="#{!empty myBean.list}".

Answer 2

<c:if> (and other JSTL tags) can be used in JSF in most cases. However, the cannot be used inside components that iterate on collections - like <h:dataTable>. But in your case, you want the <c:if> outside, so it is possible. However, as romaintaz pointed, it's better to use the rendered attribute.