@Override
        public void run() {
            counter++;
            if (speed <= 0 || counter % speed == 0) {
                speed--;
                counter = 0;
                if (increment) {
                    increase();
                } else {
                    decrease();
                }
            }
            if (speed < 0 && step < maxStep) {
                step += delta;
            }
        }
The {@link Spinner} provide two arrows for in- and decreasing values.
stroom-core-client-widget/src/main/java/stroom/widget/valuespinner/client/Spinner.java