public long get(CounterName counterName) {
    for(Map<String, Long> counterGrp : _pubCounters.values()) {
      if(counterGrp.containsKey(counterName._name)) {
        return counterGrp.get(counterName._name);
      }
    }
    return 0;
  }
Tez Counter Data defining data structure.
app/com/linkedin/drelephant/tez/data/TezCounterData.java