Method from

output/java_guava/1.4.18/Ordering.java:164–169

Returns an ordering based on an existing comparator instance. Note that it is unnecessary to create a new anonymous inner class implementing Comparator just to pass it in here. Instead, simply subclass Ordering and implement its compare method directly. @param

(Comparator<T> comparator)

   */

  @GwtCompatible(serializable = true)
  public static <T> Ordering<T> from(Comparator<T> comparator) {
    return (comparator instanceof Ordering)
      ? (Ordering<T>) comparator
      : new ComparatorOrdering<T>(comparator);
  }

  /**
   * Simply returns its argument.