public int[] getSensorTimeInterval(SensorMeta sensorMeta) { throwNull(sensorMeta); BTreeMap<Integer, ChunkMeta> chunkMetaMap = getSensorChunkMetaMap(sensorMeta); if (chunkMetaMap.isEmpty()) { return null; } return new int[] {chunkMetaMap.firstKey(), chunkMetaMap.lastEntry().getValue().lastTimestamp}; }