return network.outEdges(node);
    }

    @Override
    public EndpointPair<N> incidentNodes(E edge) {
      return network.incidentNodes(edge);
    }

    @Override
    public Set<E> adjacentEdges(E edge) {
      return network.adjacentEdges(edge);
    }

    // _don't_ override edge*Connecting*; we want the behavior from AbstractNetwork
  }

    }
    return connections;
  }

  final N checkedReferenceNode(E edge) {
    N referenceNode = edgeToReferenceNode.get(edge);
    if (referenceNode == null) {
      checkNotNull(edge);
      throw new IllegalArgumentException(String.format(EDGE_NOT_IN_GRAPH, edge));
    }
    return referenceNode;
  }

  final boolean containsNode(N node) {

    N previousNode = incidentEdgeMap.remove(edge);
    // We're relying on callers to call this method only with an edge that's in the graph.
    return requireNonNull(previousNode);
  }

  @Override
  public void addInEdge(E edge, N node, boolean isSelfLoop) {
    if (!isSelfLoop) {
      addOutEdge(edge, node);
    }
  }

  @Override
  public void addOutEdge(E edge, N node) {

    ValueGraphBuilder<N1, V1> castBuilder = cast();
    return new ImmutableValueGraph.Builder<>(castBuilder);
  }

  /**
   * Specifies whether the graph will allow self-loops (edges that connect a node to itself).
   * Attempting to add a self-loop to a graph that does not allow them will throw an {@link
   * UnsupportedOperationException}.
   *
   * <p>The default value is {@code false}.
   */

 * limitations under the License.
 */

package com.google.common.graph;

import java.util.AbstractSet;
import java.util.Set;
import javax.annotation.CheckForNull;

/**
 * Abstract base class for an incident edges set that allows different implementations of {@link
 * AbstractSet#iterator()}.
 */
@ElementTypesAreNonnullByDefault
abstract class IncidentEdgeSet<N> extends AbstractSet<EndpointPair<N>> {
  final N node;

  @Override
  public N removeInEdge(E edge, boolean isSelfLoop) {
    N node = super.removeInEdge(edge, isSelfLoop);
    Multiset<N> predecessors = getReference(predecessorsReference);
    if (predecessors != null) {
      checkState(predecessors.remove(node));
    }
    return node;
  }

  @Override
  public N removeOutEdge(E edge) {
    N node = super.removeOutEdge(edge);

   *     #allowsSelfLoops()}
   */
  @CanIgnoreReturnValue
  boolean putEdge(N nodeU, N nodeV);

  /**
   * Adds an edge connecting {@code endpoints} (in the order, if any, specified by {@code
   * endpoints}) if one is not already present.
   *
   * <p>If this graph is directed, {@code endpoints} must be ordered and the added edge will be

   *     #allowsParallelEdges()} or {@link #allowsSelfLoops()}
   */
  @CanIgnoreReturnValue
  boolean addEdge(N nodeU, N nodeV, E edge);

  /**
   * Adds {@code edge} connecting {@code endpoints}. In an undirected network, {@code edge} will
   * also connect {@code nodeV} to {@code nodeU}.
   *

    if (connections == null) {
      return false;
    }

    if (allowsSelfLoops()) {
      // Remove self-loop (if any) first, so we don't get CME while removing incident edges.
      if (connections.removeSuccessor(node) != null) {
        connections.removePredecessor(node);
        --edgeCount;
      }
    }

    for (N successor : ImmutableList.copyOf(connections.successors())) {

   *       <ul>
   *         <li>{@code edges()}: Stable order
   *         <li>{@code adjacentNodes(node)}: Connecting edge insertion order
   *         <li>{@code predecessors(node)}: Connecting edge insertion order
   *         <li>{@code successors(node)}: Connecting edge insertion order
   *         <li>{@code incidentEdges(node)}: Edge insertion order
   *       </ul>
   *   <li>For {@link Network}: