```
public class EmptyQueueSlidingWindowAggregator
extends SlidingWindowAggregator
```
When calculating MAX_TIME and LAST_VALUE (the MIN_TIME and FIRST_VALUE in descending order), the aggregation result always appears in the most recent pre-aggregation result. So, we do not need to cache the previous pre-aggregated results in the queue.

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.iotdb.db.mpp.aggregation.slidingwindow.SlidingWindowAggregator
  SlidingWindowAggregator.PartialAggregationResult

Field Summary
- Fields inherited from class org.apache.iotdb.db.mpp.aggregation.slidingwindow.SlidingWindowAggregator
  deque
- Fields inherited from class org.apache.iotdb.db.mpp.aggregation.Aggregator
  accumulator, curTimeRange, inputLocationList, step

Constructors
Constructor	Description
`EmptyQueueSlidingWindowAggregator(Accumulator accumulator, java.util.List<InputLocation[]> inputLocationList, AggregationStep step)`

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`evictingExpiredValue()`	evicting expired element in queue and reset expired aggregateResult
`void`	`processPartialResult(SlidingWindowAggregator.PartialAggregationResult partialResult)`	update queue and aggregateResult

Methods inherited from class org.apache.iotdb.db.mpp.aggregation.slidingwindow.SlidingWindowAggregator
processTsBlock, updateTimeRange

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Class EmptyQueueSlidingWindowAggregator