How to get object at specific index in Persistent Set - Grails -

i have persistent set of objects:

def applicantfiles = applicant.recommendationfiles 

how object @ ith element persistent set? tried do

applicantfiles[1] , applicantfiles.getat(1) 

neither of work.

sets can't indexed, unordered. if need index collection declare list:

to keep objects in order added , able reference them index array can define collection type list:

class author {      list books      static hasmany = [books: book] } 

with understanding associated table needs column use index. otherwise there's no way preserve ordering. can use indexcolumn specify column use:

by default when mapping indexed collection such map or list index stored in column called association_name_idx integer type in case of lists , string in case of maps. can alter how index column mapped using indexcolumn argument:

static mapping = {     matrix indexcolumn: [name: "the_matrix", type: integer] } 

http://grails.github.io/grails-doc/2.3.x/ref/database%20mapping/indexcolumn.html

if don't declare instance variable type gorm defaults type set.