final Map<E, N> outEdgeMap;

  private int selfLoopCount;

  AbstractDirectedNetworkConnections(Map<E, N> inEdgeMap, Map<E, N> outEdgeMap, int selfLoopCount) {
    this.inEdgeMap = checkNotNull(inEdgeMap);
    this.outEdgeMap = checkNotNull(outEdgeMap);
    this.selfLoopCount = checkNonNegative(selfLoopCount);
    checkState(selfLoopCount <= inEdgeMap.size() && selfLoopCount <= outEdgeMap.size());
  }

  @Override

 */
final class DirectedNetworkConnections<N, E> extends AbstractDirectedNetworkConnections<N, E> {

  DirectedNetworkConnections(Map<E, N> inEdgeMap, Map<E, N> outEdgeMap, int selfLoopCount) {
    super(inEdgeMap, outEdgeMap, selfLoopCount);
  }

  static <N, E> DirectedNetworkConnections<N, E> of() {
    return new DirectedNetworkConnections<>(

 */
final class DirectedNetworkConnections<N, E> extends AbstractDirectedNetworkConnections<N, E> {

  DirectedNetworkConnections(Map<E, N> inEdgeMap, Map<E, N> outEdgeMap, int selfLoopCount) {
    super(inEdgeMap, outEdgeMap, selfLoopCount);
  }

  static <N, E> DirectedNetworkConnections<N, E> of() {
    return new DirectedNetworkConnections<>(

 */
final class DirectedMultiNetworkConnections<N, E> extends AbstractDirectedNetworkConnections<N, E> {

  private DirectedMultiNetworkConnections(
      Map<E, N> inEdges, Map<E, N> outEdges, int selfLoopCount) {
    super(inEdges, outEdges, selfLoopCount);
  }

  static <N, E> DirectedMultiNetworkConnections<N, E> of() {
    return new DirectedMultiNetworkConnections<>(
        new HashMap<E, N>(INNER_CAPACITY, INNER_LOAD_FACTOR),

 */
final class DirectedMultiNetworkConnections<N, E> extends AbstractDirectedNetworkConnections<N, E> {

  private DirectedMultiNetworkConnections(
      Map<E, N> inEdges, Map<E, N> outEdges, int selfLoopCount) {
    super(inEdges, outEdges, selfLoopCount);
  }

  static <N, E> DirectedMultiNetworkConnections<N, E> of() {
    return new DirectedMultiNetworkConnections<>(
        new HashMap<E, N>(INNER_CAPACITY, INNER_LOAD_FACTOR),

      return IntMath.saturatedAdd(predecessors(node).size(), successors(node).size());
    } else {
      Set<N> neighbors = adjacentNodes(node);
      int selfLoopCount = (allowsSelfLoops() && neighbors.contains(node)) ? 1 : 0;
      return IntMath.saturatedAdd(neighbors.size(), selfLoopCount);
    }
  }

  @Override
  public int inDegree(N node) {
    return isDirected() ? predecessors(node).size() : degree(node);
  }