A convenient freemarker iterating directive

We are seeing the same pattern of iterating lists within freemarker appearing:

<#list items as item>
<#if item_has_next>,
<#list>

this is quite verbose, and error prone so I have added a new directive called ‘iterate’, which automatically appends a separator (default is comma) if required.

<@iterate items ; item>
whatever I want to do with the ${item}.
<@iterate>

The directive:
<#macro iterate items separator=’,’>
<#list items as item>
<#nested item/>
<#if item_has_next>${separator}<!–#if–>
<#list>
<#macro>

To use, this you need to put it into a file (i.e. mystuff.ftl) and then include it within all the templates from which you want to use the new directive (i.e. all of them ;)).

My freemarker fu sucks a bit at this point.  We have a web app so I included it in /WEB-INF/views/includes/mystuff.ftl (of course I didn’t call it that!).  Unfortunately I needed to specify the relative path as I couldn’t figure out the fully qualified one – /WEB-INF/views/includes/mystuff.ftl and /views/includes/mystuff.ftl don’t work.

So, if my template is /WEB-INF/views/people/list.ftl then I need to do the following:

<#include ../includes/mystuff.ftl>

<@iterate people ; person>
Person ${person_index}: ${person.name}
<@iterate>

We are using <a href=”http://springframework.org/”>Spring</a&gt; to configure Freemarker, which means using <a href=”http://static.springframework.org/spring/docs/2.5.x/api/org/springframework/web/servlet/view/freemarker/FreeMarkerConfigurer.html”>FreeMarkerConfigurer</a&gt;.  Unfortunately, I don’t think this supports the ability to specify <a href=”http://freemarker.sourceforge.net/docs/api/freemarker/template/Configuration.html#setAutoIncludes%28java.util.List%29″>automatic includes</a> (similar to JSP preludes and codas), so I might need to write my own.  No biggies.