Method complementOf

corpus/java/training/guava/collect/Sets.java:464–472

Creates an EnumSet consisting of all enum values that are not in the specified collection. If the collection is an EnumSet, this method has the same behavior as EnumSet#complementOf. Otherwise, the specified collection must contain at least one element, in order to determine

(Collection<E> collection)

   *     {@code EnumSet} instance and contains no elements
   */
  public static <E extends Enum<E>> EnumSet<E> complementOf(Collection<E> collection) {
    if (collection instanceof EnumSet) {
      return EnumSet.complementOf((EnumSet<E>) collection);
    }
    checkArgument(
        !collection.isEmpty(), "collection is empty; use the other version of this method");
    Class<E> type = collection.iterator().next().getDeclaringClass();
    return makeComplementByHand(collection, type);
  }

  /**
   * Creates an {@code EnumSet} consisting of all enum values that are not in