void SensorInfo::trigger(int count, TRAPS) {

  {- -------------------------------------------
  (1) sun.management.Sensor.trigger() を呼び出す.
      ---------------------------------------- -}

      assert(count <= _pending_trigger_count, "just checking");

      if (_sensor_obj != NULL) {
        klassOop k = Management::sun_management_Sensor_klass(CHECK);
        instanceKlassHandle sensorKlass (THREAD, k);
        Handle sensor_h(THREAD, _sensor_obj);
        Handle usage_h = MemoryService::create_MemoryUsage_obj(_usage, CHECK);

        JavaValue result(T_VOID);
        JavaCallArguments args(sensor_h);
        args.push_int((int) count);
        args.push_oop(usage_h);

        JavaCalls::call_virtual(&result,
                                sensorKlass,
                                vmSymbols::trigger_name(),
                                vmSymbols::trigger_method_signature(),
                                &args,
                                CHECK);
      }

  {- -------------------------------------------
  (1) Sensor の状態を on に変更し, 送信した分だけカウンタを増減しておく.
      ---------------------------------------- -}

      {
        // Holds Service_lock and update the sensor state
        MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
        _sensor_on = true;
        _sensor_count += count;
        _pending_trigger_count = _pending_trigger_count - count;
      }
    }