final transient E element;

  SingletonImmutableSet(E element) {
    this.element = Preconditions.checkNotNull(element);
  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public boolean contains(@Nullable Object target) {
    return element.equals(target);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {

    ToOptionalState<T> combine(ToOptionalState<T> other) {
      if (element == null) {
        return other;
      } else if (other.element == null) {
        return this;
      } else {
        if (extras.isEmpty()) {
          // Replace immutable empty list with mutable list.
          extras = new ArrayList<>();
        }
        extras.add(other.element);
        extras.addAll(other.extras);

        assertTrue(iterator.hasNext(), "Should have first element");
        SmbResource first = iterator.next();
        assertNotNull(first, "First element should not be null");
        assertEquals("file1.txt", first.getName());

        assertTrue(iterator.hasNext(), "Should have second element");
        SmbResource second = iterator.next();
        assertNotNull(second, "Second element should not be null");

    }

    public void renderTo(MethodDoc methodDoc, Element parent) {
        Document document = parent.getOwnerDocument();

        Element section = document.createElement("section");
        parent.appendChild(section);
        section.setAttribute("id", methodDoc.getId());
        section.setAttribute("role", "detail");

        Element title = document.createElement("title");
        section.appendChild(title);

                for (Plugin element : src) {
                    if (element.isInherited() || !element.getExecutions().isEmpty()) {
                        // NOTE: Enforce recursive merge to trigger merging/inheritance logic for executions
                        Plugin plugin = new Plugin();
                        plugin.setLocation("", element.getLocation(""));
                        plugin.setGroupId(null);

        List<Element> valueTitles = new ArrayList<Element>();
        for (int i = 1; i < header.size(); i++) {
            Element element = header.get(i);
            Element override = findChild(element, "overrides");
            if (override != null) {
                element.removeChild(override);
                inheritedValueTitleMapping.put(override.getTextContent(), element);
            }
            Node firstChild = element.getFirstChild();

  public void testElement_empty() {
    assertThrows(NoSuchElementException.class, () -> getQueue().element());
    expectUnchanged();
  }

  @CollectionSize.Require(ONE)
  public void testElement_size1() {
    assertEquals("size1Queue.element() should return first element", e0(), getQueue().element());
    expectUnchanged();
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  @CollectionSize.Require(SEVERAL)

      }
    }

    /**
     * Adds {@code element} to the {@code ImmutableSet}. If the {@code ImmutableSet} already
     * contains {@code element}, then {@code add} has no effect (only the previously added element
     * is retained).
     *
     * @param element the element to add
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code element} is null
     */
    @Override

    int expectedHashCode = 0;
    for (E element : elements) {
      expectedHashCode += (element == null) ? 0 : element.hashCode();
    }

    elements.add(null);
    collection = getSubjectGenerator().create(elements.toArray());
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements (with "
            + "a null element counting as having a hash of zero).",
        expectedHashCode,

    public static final String SELF_COMBINATION_REMOVE = "remove";
    /**
     * Default mode for combining a DOM node during merge.
     * When element names match, the process will try to merge element attributes
     * and values, rather than overriding the recessive element completely.
     */
    public static final String DEFAULT_SELF_COMBINATION_MODE = SELF_COMBINATION_MERGE;