private List<RosterEntry> findMatchingEntries(RosterComparator c){
  List<RosterEntry> l=new ArrayList<>();
  for (  RosterEntry r : _list) {
    if (c.check(r)) {
      l.add(r);
    }
  }
  return l;
}

private List < RosterEntry > findMatchingEntries ( RosterComparator c ) { List < RosterEntry > l = new ArrayList < > ( ) ; for ( RosterEntry r : _list ) { if ( c . check ( r ) ) { l . add ( r ) ; } } return l ; }
internal method works with # rostercomparator to provide a common search - match - return capability .
