private SlaveInfo[] querySlaveInfo(String arg) {
		String querySlaveName = arg;
		SlaveInfo[] response = null;
		if (querySlaveName.equals("all")) {
			Set<String> slaveSet = this.slaveTable.keySet();
			if (slaveSet != null && slaveSet.size() >= 1) {
				response = new SlaveInfo[slaveSet.size()];
				ArrayList<SlaveInfo> list = new ArrayList<SlaveInfo>();
				for (String slaveNode : slaveSet) {
					if (this.slaveTable.get(slaveNode).getNodeStatus() == NodeStatus.RUNNING) {
						list.add(this.slaveTable.get(slaveNode));
					}
				}
				if (list.size() > 0) {
					response = new SlaveInfo[list.size()];
					for (int i = 0; i < list.size(); i++) {
						response[i] = list.get(i);
					}
				}
				
				return response;
			}
		} else {
			if (this.slaveTable.containsKey(querySlaveName) && 
					this.slaveTable.get(querySlaveName).getNodeStatus() == NodeStatus.RUNNING) {
				response = new SlaveInfo[1];
				response[0] = this.slaveTable.get(querySlaveName);
			} 
		}
		return response;

	}