c:if test eq always returning true

Question

I have to check inserted date and modified date values, which both are string. If they are equal then i wont display edited email or else i will display edited email too. So i have used the below code to validate it.

<b>Created By - </b><h:outputText value="#{o.createdEmail}" /> : <h:outputText value="#{o.createdDateTime}" /><br/>                             
                                    <c:set var="createdDate" value="#{o.createdDateTime}"/>
                                    <c:set var="modifiedDate" value="#{o.modifiedDateTime}"/>
                                    <c:if test="#{createdDate eq modifiedDate}">
                                        <b>Edited By - </b><h:outputText value="#{o.lastModifiedEmail}" /> : <h:outputText value="#{o.lastModifiedDateTime}" />
                                    </c:if>

Note: o is the variable reference the backend bean.

But it is always displaying it as true even though both values are different. How is this caused and how can I solve it?

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

Given the way how the code is written (a managed bean with name o makes no utter sense), I do a educated guess that #{o} is declared as var of <h:dataTable> or <ui:repeat>. If that is indeed the case, then that would totally explain the symptoms. JSTL tags runs during view build time, that moment when the JSF component tree is built based on XHTML source code. However, JSF components such as <h:dataTable> and <ui:repeat> runs during view render time, that moment when the JSF component tree needs to produce HTML output.

So, in effects, the #{o} is not available at the moment JSTL <c:if> runs during view build time. You should instead be using a JSF component with rendered attribute which runs during view render time, the same moment as #{o} is been put in the EL variable scope based on current iteration round.

<ui:fragment rendered="#{createdDate eq modifiedDate}">
    <b>Edited By - </b><h:outputText value="#{o.lastModifiedEmail}" /> : <h:outputText value="#{o.lastModifiedDateTime}" />
</ui:fragment>

Note: this doesn't affect <c:set>. It merely creates an "alias" to the EL expression, it doesn't immediately evaluate the EL expression, so the <c:set> is completely safe here, albeit somewhat unnecessary as the value doesn't represent such a complex EL expression.

c:if test eq always returning true

1 Answers1

See also: