The Velocity SortTool allows you sort node elements in a multinode selection.

See Hannon Hill's Sort Tool knowledge base entry

The method requires these parameters:

Method addSortCriterion():

• selection string - An XPath expression specifying the node/node-set on which to sort.
• language - Specifies the two-letter ISO-639 language code to be used when sorting text data, defauls to "en".
• data type - Either "text", "number", or "qname", defaults to "text".
• sort order - Either "ascending" or "descending", defaults to "ascending".
• case order - Either "lower-first" or "upper-first", specifies whether upper-case or lower-case letters come first when sorting, defaults to "lower-first".

Then you issue a .sort method against the multinode element

<h2>My CD Collection</h2>
<table style="border: 3px solid #450084">
<tr style="background:#ccc999">
<th style="text-align:left">Title</th>
<th style="text-align:left">Artist</th>
</tr>
##LOOP
#set($cds = $_XPathTool.selectNodes($contentRoot, '//catalog/cd'))
$_SortTool.addSortCriterion("artist", "", "text", "ascending", "upper-first")
$_SortTool.sort($cds)
#foreach($cd in $cds)
#set ($artist = $cd.getChild('artist').value)
#set ($title = $cd.getChild('title').value)
<tr>
<td>$title</td>
<td>$artist</td>
</tr>
#end
##END LOOP
</table>