@Override
 public void execute(Tuple tuple) {
   Long val = (Long) tuple.getValue(0);
   collector.emit(new Values(2 * (val + 1))); // increment and double value
   collector.ack(tuple);
 }
 @Override
 public void execute(Tuple tuple) {
   Object key = tuple.getValue(1);
   Number curr = Utils.get(_sums, key, 0);
   _sums.put(key, Numbers.add(curr, tuple.getValue(2)));
 }