* to set the result of the computation through the protected methods {@link #set(Object)}, {@link
 * #setFuture(ListenableFuture)} and {@link #setException(Throwable)}. Subclasses may also override
 * {@link #afterDone()}, which will be invoked automatically when the future completes. Subclasses
 * should rarely override other methods.
 *
 * @author Sven Mawson

    assertFalse(
        from.getType() + " shouldn't be assignable to " + to.getType(), to.isSupertypeOf(from));
    assertFalse(
        to.getType() + " shouldn't be a supertype of " + from.getType(), to.isSupertypeOf(from));
    assertFalse(
        from.getType() + " shouldn't be a subtype of " + to.getType(), from.isSubtypeOf(to));
  }

    }
  }

  /**
   * On a concurrent computation that returns null, all threads should get an
   * InvalidCacheLoadException, with the loader only called once. The result should not be cached (a
   * later request should call the loader again).
   */
  private static void testConcurrentLoadingNull(CacheBuilder<Object, Object> builder)
      throws InterruptedException {

    }
  }

  /**
   * On a concurrent computation that returns null, all threads should get an
   * InvalidCacheLoadException, with the loader only called once. The result should not be cached (a
   * later request should call the loader again).
   */
  private static void testConcurrentLoadingNull(CacheBuilder<Object, Object> builder)
      throws InterruptedException {

 * allocations in many common cases.
 *
 * <p>The message string is not formatted unless the exception will be thrown, so the cost of the
 * string formatting itself should not be a concern.
 *
 * <p>As with any performance concerns, you should consider profiling your code (in a production
 * environment if possible) before spending a lot of effort on tweaking a particular element.
 *
 * <h3>Other types of preconditions</h3>
 *

 * Comparator} or {@link Comparable} type whose comparison behavior is <i>inconsistent with
 * equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting map will
 * not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=

    try {
      units.remove(SomeEnum.B);
      fail("ImmutableEnumSet should throw an exception on remove()");
    } catch (UnsupportedOperationException expected) {
    }
    try {
      units.add(SomeEnum.C);
      fail("ImmutableEnumSet should throw an exception on add()");
    } catch (UnsupportedOperationException expected) {
    }
  }

        Iterators.filter(
            unfiltered,
            new Predicate<String>() {
              @Override
              public boolean apply(String s) {
                throw new AssertionFailedError("Should never be evaluated");
              }
            });

    List<String> expected = Collections.emptyList();
    List<String> actual = Lists.newArrayList(filtered);
    assertEquals(expected, actual);
  }

  // Many of the utilities in this class (transform, withFallback, withTimeout, asList, combine)
  // have two requirements that significantly complicate their design.
  // 1. Cancellation should propagate from the returned future to the input future(s).
  // 2. The returned futures shouldn't unnecessarily 'pin' their inputs after completion.
  //
  // A consequence of these requirements is that the delegate futures cannot be stored in
  // final fields.
  //

 * Comparator} or {@link Comparable} type whose comparison behavior is <i>inconsistent with
 * equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting map will
 * not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=