SetGenerators.java 文件源码

@Override
protected SortedSet<Integer> create(Integer[] elements) {
  SortedSet<Integer> set = nullCheckedTreeSet(elements);
  if (set.isEmpty()) {
    /*
     * The (tooLow + 1, tooHigh) arguments below would be invalid because tooLow would be
     * greater than tooHigh.
     */
    return ContiguousSet.create(Range.openClosed(0, 1), DiscreteDomain.integers()).subSet(0, 1);
  }
  int tooHigh = set.last() + 1;
  int tooLow = set.first() - 1;
  set.add(tooHigh);
  set.add(tooLow);
  return checkedCreate(set).subSet(tooLow + 1, tooHigh);
}