You put the trigger operations in a propertyChange event or wherever else you have the change happening (or button press or whatever) that is the reason you want the chart to update. That's up to you. The trick is to change something on the Classic Chart that fires its internal "start over" event--just updating the plot data isn't enough. As noted in this thread, simply assigning the same value to the plot background is enough:
However, beware of the memory leak. Fixed in v8.0.6, but not yet fixed in v7.9.x.