* Returns a resolver that resolves types "invariantly".
   *
   * <p>For example, when resolving {@code List<T>} in the context of {@code ArrayList<?>}, {@code
   * <T>} cannot be invariantly resolved to {@code <?>} because otherwise the parameter type of
   * {@code List::set} will be {@code <?>} and it'll falsely say any object can be passed into
   * {@code ArrayList<?>::set}.
   *

   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#reload} if the cache
   * currently contains a value for {@code key}, and {@link CacheLoader#load} otherwise. Loading is
   * asynchronous only if {@link CacheLoader#reload} was overridden with an asynchronous
   * implementation.
   *

  }

  /**
   * Returns a cache loader that uses {@code function} to load keys, and without supporting either
   * reloading or bulk loading. This is most useful when you can pass a lambda expression. Otherwise
   * it is useful mostly when you already have an existing function instance.
   *
   * <p>The returned object is serializable if {@code function} is serializable.
   *

    addNodes(graph);

    assertThat(graph.nodeOrder()).isEqualTo(insertion());
    assertThat(graph.nodes()).containsExactly(3, 1, 4).inOrder();
  }

  // The default ordering is INSERTION unless otherwise specified.
  @Test
  public void nodeOrder_default() {
    MutableGraph<Integer> graph = GraphBuilder.directed().build();

    addNodes(graph);

    assertThat(graph.nodeOrder()).isEqualTo(insertion());

  @CheckForNull
  abstract C leastValueAbove(DiscreteDomain<C> domain);

  @CheckForNull
  abstract C greatestValueBelow(DiscreteDomain<C> domain);

  /*
   * The canonical form is a BelowValue cut whenever possible, otherwise ABOVE_ALL, or
   * (only in the case of types that are unbounded below) BELOW_ALL.
   */
  Cut<C> canonical(DiscreteDomain<C> domain) {
    return this;
  }

  // note: overridden by {BELOW,ABOVE}_ALL
  @Override

/**
 * Provides static methods for working with {@link Comparator} instances. For many other helpful
 * comparator utilities, see either {@code Comparator} itself (for Java 8+), or {@code
 * com.google.common.collect.Ordering} (otherwise).
 *
 * <h3>Relationship to {@code Ordering}</h3>
 *
 * <p>In light of the significant enhancements to {@code Comparator} in Java 8, the overwhelming

   */
  public static boolean isPowerOfTwo(int x) {
    return x > 0 & (x & (x - 1)) == 0;
  }

  /**
   * Returns 1 if {@code x < y} as unsigned integers, and 0 otherwise. Assumes that x - y fits into
   * a signed int. The implementation is branch-free, and benchmarks suggest it is measurably (if
   * narrowly) faster than the straightforward ternary expression.
   */
  @VisibleForTesting

 * <h3>For Java 8+ users</h3>
 *
 * <p>This interface is now a legacy type. Use {@code java.util.function.Predicate} (or the
 * appropriate primitive specialization such as {@code IntPredicate}) instead whenever possible.
 * Otherwise, at least reduce <i>explicit</i> dependencies on this type by using lambda expressions
 * or method references instead of classes, leaving your code easier to migrate in the future.
 *

   *
   * @param string the string to test and possibly return
   * @return {@code string} itself if it is non-null; {@code ""} if it is null
   */
  public static String nullToEmpty(@CheckForNull String string) {
    return Platform.nullToEmpty(string);
  }

  /**
   * Returns the given string if it is nonempty; {@code null} otherwise.
   *

   * Returns an array containing all of the elements in the specified collection; the runtime type
   * of the returned array is that of the specified array. If the collection fits in the specified
   * array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the
   * specified array and the size of the specified collection.
   *
   * <p>If the collection fits in the specified array with room to spare (i.e., the array has more