SourceRoot can not use in gradle

Currently inner classes are not accessible from within templates, I would like to be able to the use statement below. For the inner classes all fields, methods and constructors should also available.

<#list class.innerClasses as innerClass>
  // This is the name of the inner class: ${innerClass.name}.
</#list>

Solution direction:
Add list of ClassContainer as field to the ClassCo