beating.  Now, if you only kept on good terms with him, he'd do
almost anything you liked with the clock.  For instance, suppose
it were nine o'clock in the morning, just time to begin lessons:
you'd only have to whisper a hint to Time, and round goes the
clock in a twinkling!  Half-past one, time for dinner!'

  (`I only wish it was,' the March Hare said to itself in a
whisper.)

    }
  }

  /** A reference to a value. */
  interface ValueReference<K, V> {
    /** Returns the value. Does not block or throw exceptions. */
    @CheckForNull
    V get();

    /**
     * Waits for a value that may still be loading. Unlike get(), this method can block (in the case
     * of FutureValueReference).
     *
     * @throws ExecutionException if the loading thread throws an exception

 * "value" of a successful step or the "result" (value or exception) of any step.
 *
 * <ol>
 *   <li>A pipeline starts at its leaf step (or steps), which is created from either a callable
 *       block or a {@link ListenableFuture}.
 *   <li>Each other step is derived from one or more input steps. At each step, zero or more objects
 *       can be captured for later closing.

   *     HashBiMap.<Long, String>create());
   * ...
   * Set<Long> set = map.keySet();  // Needn't be in synchronized block
   * ...
   * synchronized (map) {  // Synchronizing on map, not set!
   *   Iterator<Long> it = set.iterator(); // Must be in synchronized block
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }</pre>
   *

    }
  }

  /** A reference to a value. */
  interface ValueReference<K, V> {
    /** Returns the value. Does not block or throw exceptions. */
    @CheckForNull
    V get();

    /**
     * Waits for a value that may still be loading. Unlike get(), this method can block (in the case
     * of FutureValueReference).
     *
     * @throws ExecutionException if the loading thread throws an exception

beating.  Now, if you only kept on good terms with him, he'd do
almost anything you liked with the clock.  For instance, suppose
it were nine o'clock in the morning, just time to begin lessons:
you'd only have to whisper a hint to Time, and round goes the
clock in a twinkling!  Half-past one, time for dinner!'

  (`I only wish it was,' the March Hare said to itself in a
whisper.)