Iterator<T> iterator, Predicate<? super T> predicate) {
    checkNotNull(predicate, "predicate");
    for (int i = 0; iterator.hasNext(); i++) {
      T current = iterator.next();
      if (predicate.apply(current)) {
        return i;
      }
    }
    return -1;
  }

  /**
   * Returns a view containing the result of applying {@code function} to each element of {@code

      Iterator<T> iterator, Predicate<? super T> predicate) {
    checkNotNull(predicate, "predicate");
    for (int i = 0; iterator.hasNext(); i++) {
      T current = iterator.next();
      if (predicate.apply(current)) {
        return i;
      }
    }
    return -1;
  }

  /**
   * Returns a view containing the result of applying {@code function} to each element of {@code