}

    @Override
    Graph<N> delegate() {
      return graph;
    }

    @Override
    public Set<N> predecessors(N node) {
      return delegate().successors(node); // transpose
    }

    @Override
    public Set<N> successors(N node) {
      return delegate().predecessors(node); // transpose
    }

    @Override
    public Set<EndpointPair<N>> incidentEdges(N node) {

 * in a {@link Network}.
 *
 * @author James Sexton
 * @param <N> Node parameter type
 * @param <E> Edge parameter type
 */
interface NetworkConnections<N, E> {

  Set<N> adjacentNodes();

  Set<N> predecessors();

  Set<N> successors();

  Set<E> incidentEdges();

  Set<E> inEdges();

  Set<E> outEdges();

  /**
   * Returns the set of edges connecting the origin node to {@code node}. For networks without

    }

    @Override
    public Set<N> adjacentNodes(N node) {
      return network.adjacentNodes(node);
    }

    @Override
    public Set<N> predecessors(N node) {
      return network.predecessors(node);
    }

    @Override
    public Set<N> successors(N node) {
      return network.successors(node);
    }

    @Override
    public Set<E> incidentEdges(N node) {

  final Map<E, N> incidentEdgeMap;

  AbstractUndirectedNetworkConnections(Map<E, N> incidentEdgeMap) {
    this.incidentEdgeMap = checkNotNull(incidentEdgeMap);
  }

  @Override
  public Set<N> predecessors() {
    return adjacentNodes();
  }

  @Override
  public Set<N> successors() {
    return adjacentNodes();
  }

  @Override
  public Set<E> incidentEdges() {

      }

      Object source = endpointPair.source();
      Object target = endpointPair.target();
      return (node.equals(source) && graph.successors(node).contains(target))
          || (node.equals(target) && graph.predecessors(node).contains(source));
    } else {
      if (endpointPair.isOrdered()) {
        return false;
      }
      Set<N> adjacent = graph.adjacentNodes(node);
      Object nodeU = endpointPair.nodeU();

  }

  @Override
  public Set<N> adjacentNodes() {
    return Collections.unmodifiableSet(adjacentNodeValues.keySet());
  }

  @Override
  public Set<N> predecessors() {
    return adjacentNodes();
  }

  @Override
  public Set<N> successors() {
    return adjacentNodes();
  }

  @Override
  public Iterator<EndpointPair<N>> incidentEdgeIterator(N thisNode) {

    return new DirectedNetworkConnections<>(
        ImmutableBiMap.copyOf(inEdges), ImmutableBiMap.copyOf(outEdges), selfLoopCount);
  }

  @Override
  public Set<N> predecessors() {
    return Collections.unmodifiableSet(((BiMap<E, N>) inEdgeMap).values());
  }

  @Override
  public Set<N> successors() {
    return Collections.unmodifiableSet(((BiMap<E, N>) outEdgeMap).values());
  }

    return new DirectedNetworkConnections<>(
        ImmutableBiMap.copyOf(inEdges), ImmutableBiMap.copyOf(outEdges), selfLoopCount);
  }

  @Override
  public Set<N> predecessors() {
    return Collections.unmodifiableSet(((BiMap<E, N>) inEdgeMap).values());
  }

  @Override
  public Set<N> successors() {
    return Collections.unmodifiableSet(((BiMap<E, N>) outEdgeMap).values());
  }

    this.selfLoopCount = checkNonNegative(selfLoopCount);
    checkState(selfLoopCount <= inEdgeMap.size() && selfLoopCount <= outEdgeMap.size());
  }

  @Override
  public Set<N> adjacentNodes() {
    return Sets.union(predecessors(), successors());
  }

  @Override
  public Set<E> incidentEdges() {
    return new AbstractSet<E>() {
      @Override
      public UnmodifiableIterator<E> iterator() {
        Iterable<E> incidentEdges =

 * transformation:
 *
 * {@snippet :
 * someGraphAlgorithm(startNode, node -> ImmutableList.of(node.leftChild(), node.rightChild()));
 * }
 *
 * <p>Graph algorithms that need additional capabilities (accessing both predecessors and
 * successors, iterating over the edges, etc.) should declare their input to be of a type that
 * provides those capabilities, such as {@link Graph}, {@link ValueGraph}, or {@link Network}.
 *