return Spliterators.spliterator(elements, SPLITERATOR_CHARACTERISTICS);
  }

  @Override
  Object[] internalArray() {
    return elements;
  }

  @Override
  int internalArrayStart() {
    return 0;
  }

  @Override
  int internalArrayEnd() {
    return elements.length;
  }

  @Override
  int copyIntoArray(@Nullable Object[] dst, int offset) {
    arraycopy(elements, 0, dst, offset, elements.length);

  /**
   * Indicates that a collection disallows certain elements (other than {@code null}, whose validity
   * as an element is indicated by the presence or absence of {@link #ALLOWS_NULL_VALUES}). From the
   * documentation for {@link Collection}:
   *
   * <blockquote>
   *
   * "Some collection implementations have restrictions on the elements that they may contain. For

        throw PermittedMetaException.ISE;
      }
    }

    private List<E> getElements() {
      List<E> elements = new ArrayList<>();
      Helpers.addAll(elements, previousElements);
      Helpers.addAll(elements, Helpers.reverse(nextElements));
      return elements;
    }
  }

  public enum KnownOrder {
    KNOWN_ORDER,
    UNKNOWN_ORDER
  }

            + " even if some elements are null.",
        getSet().equals(MinimalSet.from(elements)));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherContainsNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    elements.add(null);
    Set<E> other = MinimalSet.from(elements);

    assertFalse(

            + " even if some elements are null.",
        getSet().equals(MinimalSet.from(elements)));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherContainsNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    elements.add(null);
    Set<E> other = MinimalSet.from(elements);

    assertFalse(

 * elements FIFO (first-in-first-out). The head of the queue is that element that has been
 * on the queue the longest time. The tail of the queue is that element that has been on
 * the queue the shortest time. New elements are inserted at the tail of the queue, and the queue
 * retrieval operations obtain elements at the head of the queue.
 *

              protected List<String> create(String[] elements) {
                return new AbstractList<String>() {
                  @Override
                  public int size() {
                    return elements.length;
                  }

                  @Override
                  public String get(int index) {
                    return elements[index];
                  }
                };

              protected List<String> create(String[] elements) {
                return new AbstractList<String>() {
                  @Override
                  public int size() {
                    return elements.length;
                  }

                  @Override
                  public String get(int index) {
                    return elements[index];
                  }
                };

            UpgradeContext context, Document pomDocument) {
        Element root = pomDocument.root();

        // Extract direct values
        String groupId = root.childTextTrimmed(MavenPomElements.Elements.GROUP_ID);
        String artifactId = root.childTextTrimmed(MavenPomElements.Elements.ARTIFACT_ID);
        String version = root.childTextTrimmed(MavenPomElements.Elements.VERSION);

    final BlockingQueue<Object> q;
    final int elements;
    final CountDownLatch beganProducing = new CountDownLatch(1);
    final CountDownLatch doneProducing = new CountDownLatch(1);

    Producer(BlockingQueue<Object> q, int elements) {
      this.q = q;
      this.elements = elements;
    }

    @Override
    public @Nullable Void call() throws InterruptedException {