public abstract class CallbackMetric0<V>
extends Object
implements CallbackMetric<V>

Metric whose value is supplied when the trigger is invoked.

   CallbackMetric0<Long> hits = metricMaker.newCallbackMetric("hits", ...);
   CallbackMetric0<Long> total = metricMaker.newCallbackMetric("total", ...);
   metricMaker.newTrigger(hits, total, new Runnable() {
     public void run() {
       hits.set(1);
       total.set(5);
     }
   });