*       </ul>
   * </ul>
   *
   * @since 29.0
   */
  public static <S> ElementOrder<S> stable() {
    return new ElementOrder<>(Type.STABLE, null);
  }

  /** Returns an instance which specifies that insertion ordering is guaranteed. */
  public static <S> ElementOrder<S> insertion() {
    return new ElementOrder<>(Type.INSERTION, null);
  }

  /**

    checkArgument(
        incidentEdgeOrder.type() == ElementOrder.Type.UNORDERED
            || incidentEdgeOrder.type() == ElementOrder.Type.STABLE,
        "The given elementOrder (%s) is unsupported. incidentEdgeOrder() only supports"
            + " ElementOrder.unordered() and ElementOrder.stable().",
        incidentEdgeOrder);
    GraphBuilder<N1> newBuilder = cast();

 *
 * @author James Sexton
 */
abstract class AbstractGraphBuilder<N> {
  final boolean directed;
  boolean allowsSelfLoops = false;
  ElementOrder<N> nodeOrder = ElementOrder.insertion();
  ElementOrder<N> incidentEdgeOrder = ElementOrder.unordered();

  @Nullable Integer expectedNodeCount = null;

  /**
   * Creates a new instance with the specified edge directionality.
   *

      ElementOrder<N1> incidentEdgeOrder) {
    checkArgument(
        incidentEdgeOrder.type() == ElementOrder.Type.UNORDERED
            || incidentEdgeOrder.type() == ElementOrder.Type.STABLE,
        "The given elementOrder (%s) is unsupported. incidentEdgeOrder() only supports"
            + " ElementOrder.unordered() and ElementOrder.stable().",
        incidentEdgeOrder);

    assertThat(network.edgeOrder()).isEqualTo(ElementOrder.insertion());
    assertThat(network.edges()).containsExactly("i", "e", "p").inOrder();
    assertThat(network.nodeOrder()).isEqualTo(ElementOrder.insertion()); // default
  }

  @Test
  public void edgeOrder_natural() {
    MutableNetwork<Integer, String> network =
        NetworkBuilder.directed().edgeOrder(ElementOrder.<String>natural()).build();

  Set<EndpointPair<N>> edges();

  /**
   * Returns an {@link ElementOrder} that specifies the order of iteration for the elements of
   * {@link #edges()}, {@link #adjacentNodes(Object)}, {@link #predecessors(Object)}, {@link
   * #successors(Object)} and {@link #incidentEdges(Object)}.
   *
   * @since 29.0
   */
  ElementOrder<N> incidentEdgeOrder();

  /**

      public boolean allowsSelfLoops() {
        return AbstractValueGraph.this.allowsSelfLoops();
      }

      @Override
      public ElementOrder<N> nodeOrder() {
        return AbstractValueGraph.this.nodeOrder();
      }

      @Override
      public ElementOrder<N> incidentEdgeOrder() {
        return AbstractValueGraph.this.incidentEdgeOrder();
      }

      @Override

 * @since 20.0
 */
public final class NetworkBuilder<N, E> extends AbstractGraphBuilder<N> {
  boolean allowsParallelEdges = false;
  ElementOrder<? super E> edgeOrder = ElementOrder.insertion();
  @Nullable Integer expectedEdgeCount = null;

  /** Creates a new instance with the specified edge directionality. */
  private NetworkBuilder(boolean directed) {
    super(directed);

 * @param <V> Value parameter type
 */
class StandardValueGraph<N, V> extends AbstractValueGraph<N, V> {
  private final boolean isDirected;
  private final boolean allowsSelfLoops;
  private final ElementOrder<N> nodeOrder;

  final MapIteratorCache<N, GraphConnections<N, V>> nodeConnections;

  long edgeCount; // must be updated when edges are added or removed

class StandardNetwork<N, E> extends AbstractNetwork<N, E> {
  private final boolean isDirected;
  private final boolean allowsParallelEdges;
  private final boolean allowsSelfLoops;
  private final ElementOrder<N> nodeOrder;
  private final ElementOrder<E> edgeOrder;

  final MapIteratorCache<N, NetworkConnections<N, E>> nodeConnections;

  // We could make this a Map<E, EndpointPair<N>>. It would make incidentNodes(edge) slightly