public boolean isNullValue(int unsortedRowIndex) {
    if (unsortedRowIndex >= rowCount) {
      throw new IndexOutOfBoundsException("Index out of bound error!");
    }
    if (bitMap == null || bitMap.get(unsortedRowIndex / ARRAY_SIZE) == null) {
      return false;
    }
    int arrayIndex = unsortedRowIndex / ARRAY_SIZE;
    int elementIndex = unsortedRowIndex % ARRAY_SIZE;
    return bitMap.get(arrayIndex).isMarked(elementIndex);
  }
Get whether value is null at the given position in TvList.

@param unsortedRowIndex value index
@return boolean
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/utils/datastructure/TVList.java