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jsfelternary-operatorlogical-operators

Using && in EL results in error: The entity name must immediately follow the '&' in the entity reference

I'm trying to use a conditional expression in an el expression used in jsf, but it does not work.

<h:outputText value="#{(sel.description !=null) && (sel.description !='') ? sel.description : 'Empty description'} - "/>

but it does not work, the compiler says:

Error Traced[line: 118] The entity name must immediately follow the '&' in the entity reference.

Do you have any suggestions? Thank you!

Solution

  • You seem to be using Facelets (which is perfectly fine). It's however a XML based view technology. Everything which you write in Facelets has to be syntactically valid XML. The & is in XML a special character denoting the start of an entity like &amp;, &lt;, &gt;, &#160;, etc.

    If you would like to represent the & as-is in XML, then you'd have to replace it by &amp;.

    <h:outputText value="#{(sel.description !=null) &amp;&amp; (sel.description !='') ? sel.description : 'Empty description'} - "/>

    However, that's not pretty readable, you would rather like to use the alternative EL operator and for this (see also operators in EL for an overview of all available operators in EL):

    <h:outputText value="#{(sel.description !=null) and (sel.description !='') ? sel.description : 'Empty description'} - "/>

    All with all, this is in turn pretty clumsy as there's a simpler empty keyword for the purpose of testing both nullness and emptiness. This can in your particular case be used as:

    <h:outputText value="#{not empty sel.description ? sel.description : 'Empty description'} - "/>

    or

    <h:outputText value="#{!empty sel.description ? sel.description : 'Empty description'} - "/>

    or 

    <h:outputText value="#{empty sel.description ? 'Empty description' : sel.description} - "/>