*/
  public static class Builder<N> {

    private final MutableGraph<N> mutableGraph;

    Builder(GraphBuilder<N> graphBuilder) {
      // The incidentEdgeOrder for immutable graphs is always stable. However, we don't want to
      // modify this builder, so we make a copy instead.
      this.mutableGraph = graphBuilder.copy().incidentEdgeOrder(ElementOrder.<N>stable()).build();
    }

    /**

 * create an instance of one of the built-in implementations of {@code Graph}, use the {@link
 * GraphBuilder} class:
 *
 * {@snippet :
 * MutableGraph<Integer> graph = GraphBuilder.undirected().build();
 * }
 *
 * <p>{@link GraphBuilder#build()} returns an instance of {@link MutableGraph}, which is a subtype

 * implementors</a>
 *
 * @author Joshua O'Madadhain
 * @author Jens Nyman
 * @param <N> Node parameter type
 * @since 23.0
 */
@DoNotMock("Implement with a lambda, or use GraphBuilder to build a Graph with the desired edges")
public interface PredecessorsFunction<N> {

  /**
   * Returns all nodes in this graph adjacent to {@code node} which can be reached by traversing

 * implementors</a>
 *
 * @author Joshua O'Madadhain
 * @author Jens Nyman
 * @param <N> Node parameter type
 * @since 23.0
 */
@DoNotMock("Implement with a lambda, or use GraphBuilder to build a Graph with the desired edges")
public interface SuccessorsFunction<N> {

  /**
   * Returns all nodes in this graph adjacent to {@code node} which can be reached by traversing

    private final MutableValueGraph<N, V> mutableValueGraph;

    Builder(ValueGraphBuilder<N, V> graphBuilder) {
      // The incidentEdgeOrder for immutable graphs is always stable. However, we don't want to
      // modify this builder, so we make a copy instead.
      this.mutableValueGraph =
          graphBuilder.copy().incidentEdgeOrder(ElementOrder.<N>stable()).build();
    }

    /**

 * </ul>
 *
 * @author Jens Nyman
 * @param <N> Node parameter type
 * @since 23.1
 */
@DoNotMock(
    "Call forGraph or forTree, passing a lambda or a Graph with the desired edges (built with"
        + " GraphBuilder)")
public abstract class Traverser<N> {
  private final SuccessorsFunction<N> successorFunction;

  private Traverser(SuccessorsFunction<N> successorFunction) {
    this.successorFunction = checkNotNull(successorFunction);

  // Node order tests

  @Test
  public void nodeOrder_none() {
    MutableGraph<Integer> graph = GraphBuilder.directed().nodeOrder(unordered()).build();

    assertThat(graph.nodeOrder()).isEqualTo(unordered());
  }

  @Test
  public void nodeOrder_insertion() {
    MutableGraph<Integer> graph = GraphBuilder.directed().nodeOrder(insertion()).build();

    addNodes(graph);

 * Used to represent the order of elements in a data structure that supports different options for
 * iteration order guarantees.
 *
 * <p>Example usage:
 *
 * {@snippet :
 * MutableGraph<Integer> graph =
 *     GraphBuilder.directed().nodeOrder(ElementOrder.<Integer>natural()).build();
 * }
 *
 * @author Joshua O'Madadhain
 * @since 20.0
 */
@Immutable
public final class ElementOrder<T> {
  private final Type type;