public static List<URI> ids(Collection<? extends DataObjectRestRep> values){
  List<URI> ids=new ArrayList<URI>();
  if (values != null) {
    for (    DataObjectRestRep value : values) {
      ids.add(value.getId());
    }
  }
  return ids;
}

public static List < URI > ids ( Collection < ? extends DataObjectRestRep > values ) { List < URI > ids = new ArrayList < URI > ( ) ; if ( values != null ) { for ( DataObjectRestRep value : values ) { ids . add ( value . getId ( ) ) ; } } return ids ; }
gets a list of ids of data objects , null safe .
