for (E key : keys) {
      LockGraphNode node = new LockGraphNode(getLockName(key));
      nodes.add(node);
      map.put(key, node);
    }
    // Pre-populate all allowedPriorLocks with nodes of smaller ordinal.
    for (int i = 1; i < numKeys; i++) {
      nodes.get(i).checkAcquiredLocks(Policies.THROW, nodes.subList(0, i));
    }
    // Pre-populate all disallowedPriorLocks with nodes of larger ordinal.

   * Returns true if there is an edge that directly connects {@code nodeU} to {@code nodeV}. This is
   * equivalent to {@code nodes().contains(nodeU) && successors(nodeU).contains(nodeV)}.
   *
   * <p>In an undirected graph, this is equal to {@code hasEdgeConnecting(nodeV, nodeU)}.
   *
   * @since 23.0
   */
  boolean hasEdgeConnecting(N nodeU, N nodeV);

  /**

    checkNotNull(nodeU);
    checkNotNull(nodeV);
    return nodes().contains(nodeU) && successors(nodeU).contains(nodeV);
  }

  @Override
  public boolean hasEdgeConnecting(EndpointPair<N> endpoints) {
    checkNotNull(endpoints);
    if (!isOrderingCompatible(endpoints)) {
      return false;
    }
    N nodeU = endpoints.nodeU();
    N nodeV = endpoints.nodeV();

    GraphConnections<N, V> connectionsU = nodeConnections.get(nodeU);
    return (connectionsU != null) && connectionsU.successors().contains(nodeV);
  }

  private final @Nullable V edgeValueOrDefaultInternal(N nodeU, N nodeV, @Nullable V defaultValue) {
    GraphConnections<N, V> connectionsU = nodeConnections.get(nodeU);
    V value = (connectionsU == null) ? null : connectionsU.value(nodeV);

   * {@code edgeConnectingOrNull(nodeU, nodeV) != null}.
   *
   * <p>In an undirected network, this is equal to {@code hasEdgeConnecting(nodeV, nodeU)}.
   *
   * @since 23.0
   */
  @Override
  boolean hasEdgeConnecting(N nodeU, N nodeV);

  /**
   * Returns true if there is an edge that directly connects {@code endpoints} (in the order, if

    for (E key : keys) {
      LockGraphNode node = new LockGraphNode(getLockName(key));
      nodes.add(node);
      map.put(key, node);
    }
    // Pre-populate all allowedPriorLocks with nodes of smaller ordinal.
    for (int i = 1; i < numKeys; i++) {
      nodes.get(i).checkAcquiredLocks(Policies.THROW, nodes.subList(0, i));
    }
    // Pre-populate all disallowedPriorLocks with nodes of larger ordinal.

      return (node.equals(source) && successorsOrEmpty(node).contains(target))
          || (node.equals(target) && predecessorsOrEmpty(node).contains(source));
    } else {
      Set<N> adjacent = graph.adjacentNodes(node);
      Object nodeU = endpointPair.nodeU();
      Object nodeV = endpointPair.nodeV();

      return (node.equals(nodeV) && adjacent.contains(nodeU))

      return (node.equals(source) && successorsOrEmpty(node).contains(target))
          || (node.equals(target) && predecessorsOrEmpty(node).contains(source));
    } else {
      Set<N> adjacent = graph.adjacentNodes(node);
      Object nodeU = endpointPair.nodeU();
      Object nodeV = endpointPair.nodeV();

      return (node.equals(nodeV) && adjacent.contains(nodeU))

        assertThat(graph.degree(node)).isEqualTo(graph.adjacentNodes(node).size() + selfLoopCount);
        assertThat(graph.predecessors(node)).isEqualTo(graph.adjacentNodes(node));
        assertThat(graph.successors(node)).isEqualTo(graph.adjacentNodes(node));
        assertThat(graph.inDegree(node)).isEqualTo(graph.degree(node));
        assertThat(graph.outDegree(node)).isEqualTo(graph.degree(node));

  public void validateUndirectedEdges() {
    for (Integer node : network.nodes()) {
      new EqualsTester()
          .addEqualityGroup(
              network.inEdges(node), network.outEdges(node), network.incidentEdges(node))
          .testEquals();
      new EqualsTester()
          .addEqualityGroup(
              network.predecessors(node), network.successors(node), network.adjacentNodes(node))
          .testEquals();