Grails: Sorting Nested Domain Objects -

i've got 1 many relationship in.
have application has multiple files can uploaded it. application view contains uploaded file list (the files in list contain meta data file such file name, file size etc.). having trouble ability sort nested list.
using sortablecolumn call sort action in controller.
how can retrieve application , specify nested list of uploaded files sorted requested attribute (ex. file name, file size etc.)

edit:
here snippets:

here application domain object

class application implements serializable {      private static final long serialversionuid = 1      firm firm      static hasmany = [applicationdocumentholders:applicationdocumentholder]      static belongsto = [firm:firm]     static mapping = {firm lazy: false} } 

and here application document holder (i storing actual documents in mongodb , meta data in sqlserver in applicationdocumentholder object, sake of simplicity leaving out document file not pertain question)

import java.sql.time  class applicationdocumentholder implements serializable {      private static final long serialversionuid = 1      static belongsto = [application:application]      static mapping = {application lazy: false}      application application     applicationdocumenttype type     applicationdocumentstatus status     date verfieddate     long uploadfileid     //following fields null until file uploaded     string filename     date uploaddate     string uploaduserid     long filesize      static constraints = {         type blank: false         status blank: false         verfieddate nullable: true         uploadfileid nullable: true         uploadfile nullable: true         filename nullable: true         uploaddate nullable: true         uploaduserid nullable: true         filesize nullable: true     } } 

here snippet gsp using sortablecolumn tag call sort action in controller

<g:sortablecolumn action="sort" property="type" title="${message(code: 'applicationdocumentholder.type.label', default: 'type')}" />  <g:sortablecolumn action="sort" property="status" title="${message(code: 'applicationdocumentholder.status.label', default: 'status')}" />  <g:sortablecolumn action="sort" property="verfieddate" title="${message(code: 'applicationdocumentholder.verfieddate.label', default: 'verfied date')}" />  <g:sortablecolumn action="sort" property="filename" title="${message(code: 'applicationdocumentholder.uploadfilename.label', default: 'upload file name')}" /> 

i wondering best way is.
can sort collection of applicationdocumentholders in controller keep getting violations because these attached objects db.
can re-retrieve list sorted not sure how specify want dynamically sorted nested object when retrieved db (i know there must simple way pretty new grails).

i know how both way future reference.

you can create simple closure takes attribute want sort , file. can closure.curry(attributename) closure new closure sorts attribute. then, pass closure collection.tosorted() sort list of files.

def files = [     [name: 'foo.txt', size: 10],     [name: 'bar.txt', size: 30],     [name: 'hello.txt', size: 20] ]  def sorter = { attr, file -> file[attr] }  files.tosorted sorter.curry('size') // sort size files.tosorted sorter.curry('name') // sort name