findAll 
Purpose
Uses the Groovy JDK findAll method to iterate over each element of the specified object that match the GPath expression within the attribute "expr"Examples
Stephen King's Books:
<g:findAll in="${books}" expr="it.author == 'Stephen King'">
     <p>Title: ${it.title}</p>
</g:findAll> 
Description
Attributes
in - The object to iterative over 
expr - A GPath expression