return new DirectedGraphConnections<>(
        adjacentNodeValues,
        orderedNodeConnectionsBuilder.build(),
        predecessorCount,
        successorCount);
  }

  @Override
  public Set<N> adjacentNodes() {
    if (orderedNodeConnections == null) {
      return Collections.unmodifiableSet(adjacentNodeValues.keySet());
    } else {
      return new AbstractSet<N>() {
        @Override

      return predecessorsOrEmpty(node).size()
          + successorsOrEmpty(node).size()
          - (edgeType == EdgeType.BOTH && predecessorsOrEmpty(node).contains(node) ? 1 : 0);
    } else {
      return graph.adjacentNodes(node).size();
    }
  }

  @Override
  public boolean contains(@Nullable Object obj) {
    if (!(obj instanceof EndpointPair)) {
      return false;
    }

    return graph.isDirected()
        ? DirectedGraphConnections.ofImmutable(node, graph.incidentEdges(node), edgeValueFn)
        : UndirectedGraphConnections.ofImmutable(
            Maps.asMap(graph.adjacentNodes(node), edgeValueFn));
  }

  @Override
  BaseGraph<N> delegate() {
    return backingGraph;
  }

  /**
   * A builder for creating {@link ImmutableGraph} instances, especially {@code static final}

    assertThat(asNetwork.allowsParallelEdges()).isFalse();
    assertThat(asNetwork.asGraph()).isEqualTo(graph.asGraph());

    for (Integer node : graph.nodes()) {
      assertThat(graph.adjacentNodes(node)).isEqualTo(asGraph.adjacentNodes(node));
      assertThat(graph.predecessors(node)).isEqualTo(asGraph.predecessors(node));
      assertThat(graph.successors(node)).isEqualTo(asGraph.successors(node));

    assertThat(asNetwork.allowsParallelEdges()).isFalse();
    assertThat(asNetwork.asGraph()).isEqualTo(graph.asGraph());

    for (Integer node : graph.nodes()) {
      assertThat(graph.adjacentNodes(node)).isEqualTo(asGraph.adjacentNodes(node));
      assertThat(graph.predecessors(node)).isEqualTo(asGraph.predecessors(node));
      assertThat(graph.successors(node)).isEqualTo(asGraph.successors(node));

        ? DirectedGraphConnections.ofImmutable(
            node, graph.incidentEdges(node), successorNodeToValueFn)
        : UndirectedGraphConnections.ofImmutable(
            Maps.asMap(graph.adjacentNodes(node), successorNodeToValueFn));
  }

  /**
   * A builder for creating {@link ImmutableValueGraph} instances, especially {@code static final}
   * graphs. Example:
   *
   * {@snippet :

    assertThat(ordered.target()).isEqualTo("target");
    assertThat(ordered.nodeU()).isEqualTo("source");
    assertThat(ordered.nodeV()).isEqualTo("target");
    assertThat(ordered.adjacentNode("source")).isEqualTo("target");
    assertThat(ordered.adjacentNode("target")).isEqualTo("source");
    assertThat(ordered.toString()).isEqualTo("<source -> target>");
  }

  @Test
  public void testUnorderedEndpointPair() {

    assertThat(ordered.target()).isEqualTo("target");
    assertThat(ordered.nodeU()).isEqualTo("source");
    assertThat(ordered.nodeV()).isEqualTo("target");
    assertThat(ordered.adjacentNode("source")).isEqualTo("target");
    assertThat(ordered.adjacentNode("target")).isEqualTo("source");
    assertThat(ordered.toString()).isEqualTo("<source -> target>");
  }

  @Test
  public void testUnorderedEndpointPair() {

   * returns an arbitrary (but consistent) endpoint of the origin edge.
   */
  public final N nodeU() {
    return nodeU;
  }

  /**
   * Returns the node {@link #adjacentNode(Object) adjacent} to {@link #nodeU()} along the origin
   * edge. If this {@link EndpointPair} {@link #isOrdered()}, this is equal to {@link #target()}.
   */
  public final N nodeV() {
    return nodeV;
  }

  static final String NOT_AVAILABLE_ON_UNDIRECTED =
      "Cannot call source()/target() on a EndpointPair from an undirected graph. Consider calling "
          + "adjacentNode(node) if you already have a node, or nodeU()/nodeV() if you don't.";
  static final String EDGE_ALREADY_EXISTS = "Edge %s already exists in the graph.";
  static final String ENDPOINTS_MISMATCH =