@Override
        public void reduce(NullObject key, Iterator<Integer> values, ReduceEmitter<NullObject, Integer> emitter) {
            int sum = 0;
            while (values.hasNext()) {
                sum = sum + values.next();
            }
            emitter.emit(sum);
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/computer/GraphComputerTest.java