public static List<String> stringRefIds(Collection<? extends RelatedResourceRep> refs){
  List<String> ids=new ArrayList<String>();
  if (refs != null) {
    for (    RelatedResourceRep ref : refs) {
      ids.add(stringId(ref));
    }
  }
  return ids;
}

public static List < String > stringRefIds ( Collection < ? extends RelatedResourceRep > refs ) { List < String > ids = new ArrayList < String > ( ) ; if ( refs != null ) { for ( RelatedResourceRep ref : refs ) { ids . add ( stringId ( ref ) ) ; } } return ids ; }
gets the ids of the references , as a list of strings .
