Method subMap

output/java_guava/1.4.18/Maps.java:4228–4246

Returns a view of the portion of map whose keys are contained by range. This method delegates to the appropriate methods of NavigableMap (namely NavigableMap#subMap(Object, boolean, Object, boolean) subMap(), NavigableMap#tailMap(Object, boolean) tailMap()

(NavigableMap<K, V> map, Range<K> range)

   */

  @Beta
  @GwtIncompatible // NavigableMap
  public static <K extends Comparable<? super K>, V> NavigableMap<K, V> subMap(NavigableMap<K, V> map, Range<K> range) {
    if (map.comparator() != null && map.comparator() != Ordering.natural()
        && range.hasLowerBound()
        && range.hasUpperBound()) {
      checkArgument(map.comparator().compare(range.lowerEndpoint(), range.upperEndpoint()) <= 0, "map is using a custom comparator which is inconsistent with the natural ordering.");
    }
    if (range.hasLowerBound() && range.hasUpperBound()) {
      return map.subMap(
        range.lowerEndpoint(), range.lowerBoundType() == BoundType.CLOSED,
        range.upperEndpoint(), range.upperBoundType() == BoundType.CLOSED);
    } else if (range.hasLowerBound()) {
      return map.tailMap(range.lowerEndpoint(), range.lowerBoundType() == BoundType.CLOSED);
    } else if (range.hasUpperBound()) {
      return map.headMap(range.upperEndpoint(), range.upperBoundType() == BoundType.CLOSED);
    }
    return checkNotNull(map);
  }
}