[FIXED] How to return the next element from a spliterator in java

Issue

I want to get the next element from a spliterator, not just "perform action" on the next element. For example by implementing the following method

<T> T getnext(Spliterator<T> s) {

}

All search results I found just said that tryAdvance() was like a combination of an iterators hasNext() and next(), except that is a BIG LIE because I can't get next element, just "perform action on next element".

Solution

You can wrap the item in a list and then return from that list:

    public static <T> T getNext(Spliterator<T> spliterator) {
        List<T> result = new ArrayList<>(1);

        if (spliterator.tryAdvance(result::add)) {
            return result.get(0);
        } else {
            return null;
        }
    }

To make it more obvious to the caller that this is an operation that may return null, consider returning Optional:

    public static <T> Optional<T> getNext(Spliterator<T> spliterator) {
        final List<T> result = new ArrayList<>(1);

        if (spliterator.tryAdvance(result::add)) {
            return Optional.of(result.get(0));
        } else {
            return Optional.empty();
        }
    }

Answered By - Felix

Answer Checked By - Timothy Miller (PHPFixing Admin)