public static SupervisorSummary mkSupervisorSummary(
SupervisorInfo supervisorInfo, String supervisorId,
Map<String, Integer> supervisorToUsedSlotNum) {
Integer usedNum = supervisorToUsedSlotNum.get(supervisorId);
SupervisorSummary summary = new SupervisorSummary(
supervisorInfo.getHostName(), supervisorId,
supervisorInfo.getUptimeSecs(), supervisorInfo.getWorkerPorts()
.size(), usedNum == null ? 0 : usedNum);
return summary;