Tuesday, November 8, 2011

Default / Legacy variables in JSTL

So I've been working with JSTL, JSF and Facelets for a while now and didn't come across a decent post on how to default values or work with legacy varibles (i.e. you had renamed your f:param to a component).

The solution is to use a combination of c:if and c:set tags, like the following:

<c:if test="#{empty optionalVar}">
  <c:set var="optionalVar" scope="page" value="#{defaultValue}"/>
<!-- or -->
<c:if test="#{empty newVarName}">
  <c:set var="newVarName" scope="page" value="#{oldVarName}"/>

This has been working great for me.  I've been digging around for decent articles on how else f:param and f:attributes are used and found a great one called Communication in JSF.

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