Class FutureConstants

future-java/src/main/java/io/trane/future/Future.java:607–615

}

final class FutureConstants {

  private FutureConstants() {
  }

  static final Future<?> NEVER = new NoFuture<>();
  static final Future<? extends List<?>> EMPTY_LIST = Future.value(Collections.unmodifiableList(new ArrayList<>(0)));
  static final Future<? extends Optional<?>> EMPTY_OPIONAL = Future.value(Optional.empty());
}

final class CollectPromise<T> extends Promise<List<T>> {