public Item next() {
                if (!hasNext())
                    throw new NoSuchElementException(this + " has no more elements");

                currentIndex++;
                if ((phrase.matched instanceof MatchedWord))
                    return ((MatchedWord)phrase.matched).getItem();
                else
                    return phrase.getOwner().getItem(phrase.getStartIndex()+currentIndex-1);
            }
Returns the value to replace the item last returned by next(), or null to keep it as-is
container-search/src/main/java/com/yahoo/prelude/querytransform/PhraseMatcher.java