IncidentEdgeSet<N> incident =
        new IncidentEdgeSet<N>(this, node, IncidentEdgeSet.EdgeType.BOTH) {
          @Override
          public Iterator<EndpointPair<N>> iterator() {
            return connections.incidentEdgeIterator(node);
          }
        };
    return nodeInvalidatableSet(incident, node);
  }

  @Override

        }
    }

    /**
     * {@inheritDoc}
     *
     * @see java.util.Iterator#hasNext()
     */
    @Override
    public boolean hasNext() {
        return this.next != null;
    }

    /**
     * {@inheritDoc}
     *
     * @see java.util.Iterator#next()
     */
    @Override
    public FileEntry next() {
        final FileEntry n = this.next;

        if ((coreExtensions.getExtensions() != null)
                && (coreExtensions.getExtensions().size() > 0)) {
            for (Iterator iter = coreExtensions.getExtensions().iterator(); iter.hasNext(); ) {
                CoreExtension o = (CoreExtension) iter.next();
                writeCoreExtension(o, "extension", serializer);
            }
        }

     */
    public boolean isChildOfRootNode() {
        return parent != null && parent.parent == null;
    }

    public Iterator<ResolutionNode> getChildrenIterator() {
        return children.iterator();
    }

    public int getDepth() {
        return depth;
    }

    public List<ArtifactRepository> getRemoteRepositories() {
        return remoteRepositories;

  public SampleElements(E e0, E e1, E e2, E e3, E e4) {
    this.e0 = e0;
    this.e1 = e1;
    this.e2 = e2;
    this.e3 = e3;
    this.e4 = e4;
  }

  @Override
  public Iterator<E> iterator() {
    return asList().iterator();
  }

  public List<E> asList() {
    return Arrays.asList(e0(), e1(), e2(), e3(), e4());
  }

  public static class Strings extends SampleElements<String> {
    public Strings() {

  public void testAddAllConcurrentWithIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<E> iterator = collection.iterator();
          assertTrue(collection.addAll(MinimalCollection.of(e3(), e0())));
          iterator.next();
        });
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)

  }

  @Override
  Iterator<Entry<E>> entryIterator() {
    // AbstractIterator makes this fairly clean, but it doesn't support remove(). To support
    // remove(), we create an AbstractIterator, and then use ForwardingIterator to delegate to it.
    Iterator<Entry<E>> readOnlyIterator =
        new AbstractIterator<Entry<E>>() {
          private final Iterator<Map.Entry<E, AtomicInteger>> mapEntries =

        () -> {
          Iterator<String> iterator = values.iterator();
          iterator.next();
          iterator.remove();
        });

    Set<Entry<Integer, String>> entries = unmod.entrySet();
    assertThrows(
        UnsupportedOperationException.class,
        () -> {
          Iterator<Entry<Integer, String>> iterator = entries.iterator();
          iterator.next();

    TreeMultimap<String, Integer> multimap = createPopulate();
    Iterator<Entry<String, Collection<Integer>>> iterator = multimap.asMap().entrySet().iterator();
    Entry<String, Collection<Integer>> entry = iterator.next();
    assertThat(entry.getKey()).isEqualTo("foo");
    assertThat(entry.getValue()).containsExactly(1, 3, 7);
    entry = iterator.next();
    assertThat(entry.getKey()).isEqualTo("google");

  final transient Collection<E> delegate;

  ForwardingImmutableCollection(Collection<E> delegate) {
    this.delegate = delegate;
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return Iterators.unmodifiableIterator(delegate.iterator());
  }

  @Override
  public boolean contains(@Nullable Object object) {
    return object != null && delegate.contains(object);
  }

  @Override