protected void increase() {
        value += step;
        if (constrained && value > max) {
            if (wrapValues) {
                value = min;
            } else {
                value = max;
                timer.cancel();
            }
        }
        ValueChangeEvent.fire(this, value);
    }
Increases the current value of the spinner by adding current step
stroom-core-client-widget/src/main/java/stroom/widget/valuespinner/client/Spinner.java