code: @Override
  	public T next() {
  		if (hasNext()) {
  			T current = next;
  			next = null;
  			return current;
  		} else {
  			throw new NoSuchElementException();
  		}
  	}
docs: Returns the next element of the DataStream. (Blocks if it is not available yet.)
  @return The element
  @throws NoSuchElementException if the stream has already ended