private Platform() {}

  static CharMatcher precomputeCharMatcher(CharMatcher matcher) {
    return matcher.precomputedInternal();
  }

  static <T extends Enum<T>> Optional<T> getEnumIfPresent(Class<T> enumClass, String value) {
    WeakReference<? extends Enum<?>> ref = Enums.getEnumConstants(enumClass).get(value);
    return ref == null ? Optional.<T>absent() : Optional.of(enumClass.cast(ref.get()));
  }

   *
   * @since 12.0
   */
  public static <T extends Enum<T>> Optional<T> getIfPresent(Class<T> enumClass, String value) {
    checkNotNull(enumClass);
    checkNotNull(value);
    return Platform.getEnumIfPresent(enumClass, value);
  }

  @GwtIncompatible // java.lang.ref.WeakReference
  private static final Map<Class<? extends Enum<?>>, Map<String, WeakReference<? extends Enum<?>>>>
      enumConstantCache = new WeakHashMap<>();

  private Platform() {}

  static CharMatcher precomputeCharMatcher(CharMatcher matcher) {
    return matcher.precomputedInternal();
  }

  static <T extends Enum<T>> Optional<T> getEnumIfPresent(Class<T> enumClass, String value) {
    WeakReference<? extends Enum<?>> ref = Enums.getEnumConstants(enumClass).get(value);
    /*
     * We use `fromNullable` instead of `of` because `WeakReference.get()` has a nullable return

   *
   * @since 12.0
   */
  public static <T extends Enum<T>> Optional<T> getIfPresent(Class<T> enumClass, String value) {
    checkNotNull(enumClass);
    checkNotNull(value);
    return Platform.getEnumIfPresent(enumClass, value);
  }

  @GwtIncompatible // java.lang.ref.WeakReference
  private static final Map<Class<? extends Enum<?>>, Map<String, WeakReference<? extends Enum<?>>>>
      enumConstantCache = new WeakHashMap<>();