*/
@GwtCompatible
public class Joiner {
  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(String separator) {
    return new Joiner(separator);
  }

  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(char separator) {
    return new Joiner(String.valueOf(separator));
  }

  /**
   * A collector that converts a stream of zero or one elements to an {@code Optional}.
   *
   * @throws IllegalArgumentException if the stream consists of two or more elements.
   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be
   *     {@code null}) and returns {@code Optional.empty()} if it has none.

  public SampleElements<Entry<K, V>> samples() {
    return SampleElements.mapEntries(keys, values);
  }

  @Override
  public Set<Entry<K, V>> create(Object... elements) {
    Entry<K, V>[] entries = createArray(elements.length);
    arraycopy(elements, 0, entries, 0, elements.length);
    return createFromEntries(entries);
  }

  public abstract Set<Entry<K, V>> createFromEntries(Entry<K, V>[] entries);

  @Override

  public SampleElements<Entry<K, V>> samples() {
    return SampleElements.mapEntries(keys, values);
  }

  @Override
  public Set<Entry<K, V>> create(Object... elements) {
    Entry<K, V>[] entries = createArray(elements.length);
    arraycopy(elements, 0, entries, 0, elements.length);
    return createFromEntries(entries);
  }

  public abstract Set<Entry<K, V>> createFromEntries(Entry<K, V>[] entries);

  @Override

    return new Enums();
  }

  @Override
  public Multiset<AnEnum> create(Object... elements) {
    AnEnum[] array = new AnEnum[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (AnEnum) e;
    }
    return create(array);
  }

  protected abstract Multiset<AnEnum> create(AnEnum[] elements);

  @Override
  public AnEnum[] createArray(int length) {
    return new AnEnum[length];

  }

  @SafeVarargs
  @CanIgnoreReturnValue
  public final Ordered expect(Object... elements) {
    return expect(asList(elements));
  }

  @CanIgnoreReturnValue
  public final Ordered expect(Iterable<?> elements) {
    List<List<E>> resultsForAllStrategies = new ArrayList<>();
    for (Supplier<GeneralSpliterator<E>> spliteratorSupplier : spliteratorSuppliers) {

  }

  @SafeVarargs
  @CanIgnoreReturnValue
  public final Ordered expect(Object... elements) {
    return expect(asList(elements));
  }

  @CanIgnoreReturnValue
  public final Ordered expect(Iterable<?> elements) {
    List<List<E>> resultsForAllStrategies = new ArrayList<>();
    for (Supplier<GeneralSpliterator<E>> spliteratorSupplier : spliteratorSuppliers) {

        SortedMultisetTestSuiteBuilder.using(
                new TestStringMultisetGenerator() {
                  @Override
                  protected Multiset<String> create(String[] elements) {
                    return TreeMultiset.create(asList(elements));
                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {

                new TestStringCollectionGenerator() {
                  @Override
                  protected Collection<String> create(String[] elements) {
                    return new StandardImplForwardingCollection<>(
                        new LinkedList<>(asList(elements)));
                  }
                })
            .named("ForwardingCollection[LinkedList] with standard implementations")
            .withFeatures(

  public static Test suite() {
    return SetTestSuiteBuilder.using(
            new TestStringSetGenerator() {
              @Override
              protected Set<String> create(String[] elements) {
                return MinimalSet.of(elements);
              }
            })
        .named("MinimalSet")
        .withFeatures(
            CollectionFeature.ALLOWS_NULL_VALUES, CollectionFeature.NONE, CollectionSize.ANY)