public void of(Matcher<? super T> matcher) {
    if (optionalValue.isPresent()) {
      Checkers.check(optionalValue.get()).is(matcher);
    } else {
      // We fail any matcher on absent value in this check
      ObjectChecker.fail(optionalValue, matcher);
    }
  }
The optional match wrapper.
@param <T> the generic type
testing/src/org/immutables/check/OptionalChecker.java