Question

I’ve been searching for a way to create a custom JSTL tag that returns an object or map instead of just using out.print to dump the markup directly from the code.

Specifically, what I’m trying to do:

<c:set var="links">
    <util:getLinks cmsComponent="[id of some xml structure]" xPath="[start point]" />
</c:set>

<!-- parse the obtained structure into a nice ul -->

I know I can:

• use my controller to do this and pass the computed object back in the view. Unfortunately the CMS we have to use makes this a lot uglier than it would be to do it in the view – getting the component id in the Java code is a pain. I know it sucks.
• make an EL function that returns the object and do:
  <c:set var="links" value="${util:getLinks(componentId, xPath)}" />
  I’m curious if I can do this using a custom tag since I couldn’t find anything by googling.

Answer 1

Sure, the tag should simply put its result in the PageContext. An attribute should specify the name under which it will be present. That’s the way <c:url /> works, for example – you can specify var and the result will be accessible by that name.

<util:getLinks cmsComponent=".." xPath=".." var="links" />