* @author Chris Povirk
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Sets {
  private Sets() {}

  /**
   * {@link AbstractSet} substitute without the potentially-quadratic {@code removeAll}
   * implementation.
   */
  abstract static class ImprovedAbstractSet<E extends @Nullable Object> extends AbstractSet<E> {
    @Override

    TypeToken<Map<String, Integer>> reserialized =
        reserialize(new TypeToken<Map<String, Integer>>() {});
    assertEquals(reserialized, substitute(reserialized, String.class));
  }

  private static <T, X> TypeToken<T> substitute(TypeToken<T> type, Class<X> arg) {
    return type.where(new TypeParameter<X>() {}, arg);
  }

   * object behaves appropriately when its thread is interrupted.
   *
   * <p>For example, to return the value of {@code target.someMethod()}, but substitute {@code
   * DEFAULT_VALUE} if this method call takes over 50 ms, you can use this code:
   *
   * <pre>
   *   TimeLimiter limiter = . . .;
   *   TargetType proxy = limiter.newProxy(

   *     errorMessageArgs[0]}, etc. Unmatched arguments will be appended to the formatted message in
   *     square braces. Unmatched placeholders will be left as-is.
   * @param errorMessageArgs the arguments to be substituted into the message template. Arguments
   *     are converted to strings using {@link String#valueOf(Object)}.
   * @throws IllegalArgumentException if {@code expression} is false
   */
  public static void checkArgument(

 * <ul>
 *   <li>The raw {@code long} values returned by {@code nanoTime} are meaningless and unsafe to use
 *       in any other way than how {@code Stopwatch} uses them.
 *   <li>An alternative source of nanosecond ticks can be substituted, for example for testing or
 *       performance reasons, without affecting most of your code.
 * </ul>
 *
 * <p>The one downside of {@code Stopwatch} relative to {@link System#nanoTime()} is that {@code

 * <ul>
 *   <li>The raw {@code long} values returned by {@code nanoTime} are meaningless and unsafe to use
 *       in any other way than how {@code Stopwatch} uses them.
 *   <li>An alternative source of nanosecond ticks can be substituted, for example for testing or
 *       performance reasons, without affecting most of your code.
 * </ul>
 *
 * <p>The one downside of {@code Stopwatch} relative to {@link System#nanoTime()} is that {@code

    ImmutableList<Service> copy = ImmutableList.copyOf(services);
    if (copy.isEmpty()) {
      // Having no services causes the manager to behave strangely. Notably, listeners are never
      // fired. To avoid this we substitute a placeholder service.
      logger
          .get()
          .log(
              Level.WARNING,
              "ServiceManager configured with no services.  Is your application configured"

  /** Returns the represented type. */
  public final Type getType() {
    return runtimeType;
  }

  /**
   * Returns a new {@code TypeToken} where type variables represented by {@code typeParam} are
   * substituted by {@code typeArg}. For example, it can be used to construct {@code Map<K, V>} for
   * any {@code K} and {@code V} type:
   *
   * <pre>{@code
   * static <K, V> TypeToken<Map<K, V>> mapOf(

    assertNull(map.put(one, two));

    assertThat(map).containsEntry(three, one);
    assertThat(map).containsEntry(one, two);

    // TODO(cgruber): Confirm with fry@ that this is a reasonable substitute.
    // Set<Entry<Object, Object>> entries = map.entrySet();
    // assertThat(entries).containsExactly(
    //    Maps.immutableEntry(three, one), Maps.immutableEntry(one, two));
    // Set<Object> keys = map.keySet();

    assertNull(map.put(one, two));

    assertThat(map).containsEntry(three, one);
    assertThat(map).containsEntry(one, two);

    // TODO(cgruber): Confirm with fry@ that this is a reasonable substitute.
    // Set<Entry<Object, Object>> entries = map.entrySet();
    // assertThat(entries).containsExactly(
    //    Maps.immutableEntry(three, one), Maps.immutableEntry(one, two));
    // Set<Object> keys = map.keySet();