* @since 20.0
 */
@Beta
@ElementTypesAreNonnullByDefault
public abstract class AbstractValueGraph<N, V> extends AbstractBaseGraph<N>
    implements ValueGraph<N, V> {

  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractValueGraph.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {

    mutableNetwork.addNode("A");
    ImmutableNetwork<String, Integer> immutableNetwork = ImmutableNetwork.copyOf(mutableNetwork);

    assertThat(immutableNetwork.asGraph()).isInstanceOf(ImmutableGraph.class);
    assertThat(immutableNetwork).isNotInstanceOf(MutableNetwork.class);
    assertThat(immutableNetwork).isEqualTo(mutableNetwork);

    mutableNetwork.addNode("B");

    mutableValueGraph.addNode("A");
    ImmutableValueGraph<String, Integer> immutableValueGraph =
        ImmutableValueGraph.copyOf(mutableValueGraph);

    assertThat(immutableValueGraph.asGraph()).isInstanceOf(ImmutableGraph.class);
    assertThat(immutableValueGraph).isNotInstanceOf(MutableValueGraph.class);
    assertThat(immutableValueGraph).isEqualTo(mutableValueGraph);

    mutableValueGraph.addNode("B");

    return checkNotNull(graph);
  }

  @Override
  public ElementOrder<N> incidentEdgeOrder() {
    return ElementOrder.stable();
  }

  @Override
  public ImmutableGraph<N> asGraph() {
    return new ImmutableGraph<>(this); // safe because the view is effectively immutable
  }

  private static <N, V> ImmutableMap<N, GraphConnections<N, V>> getNodeConnections(
      ValueGraph<N, V> graph) {

  }

  @Test
  public void edges_containsOrderMismatch() {
    addEdge(N1, N2, E12);
    assertThat(network.asGraph().edges()).doesNotContain(ENDPOINTS_N2N1);
    assertThat(network.asGraph().edges()).doesNotContain(ENDPOINTS_N1N2);
  }

  @Test
  public void edgesConnecting_orderMismatch() {
    addEdge(N1, N2, E12);
    IllegalArgumentException e =

    return checkNotNull(graph);
  }

  @Override
  public ElementOrder<N> incidentEdgeOrder() {
    return ElementOrder.stable();
  }

  @Override
  public ImmutableGraph<N> asGraph() {
    return new ImmutableGraph<>(this); // safe because the view is effectively immutable
  }

  private static <N, V> ImmutableMap<N, GraphConnections<N, V>> getNodeConnections(
      ValueGraph<N, V> graph) {

    assertThat(transpose).isEqualTo(expectedTranspose);
    assertThat(transpose(transpose)).isSameInstanceAs(directedGraph);
    AbstractGraphTest.validateGraph(transpose.asGraph());

    assertThat(transpose.edgeValueOrDefault(N1, N2, null)).isNull();
    for (Integer node : directedGraph.nodes()) {
      assertThat(directedGraph.inDegree(node)).isSameInstanceAs(transpose.outDegree(node));

 * @param <E> Edge parameter type
 * @since 20.0
 */
@Beta
@ElementTypesAreNonnullByDefault
public abstract class AbstractNetwork<N, E> implements Network<N, E> {
  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractNetwork.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {

 * @param <E> Edge parameter type
 * @since 20.0
 */
@Beta
@ElementTypesAreNonnullByDefault
public abstract class AbstractNetwork<N, E> implements Network<N, E> {
  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractNetwork.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {

  /**
   * Returns a live view of this graph as a {@link Graph}. The resulting {@link Graph} will have an
   * edge connecting node A to node B if this {@link ValueGraph} has an edge connecting A to B.
   */
  Graph<N> asGraph();

  //
  // ValueGraph properties
  //

  /**
   * Returns true if the edges in this graph are directed. Directed edges connect a {@link