java.lang.Object
- org.apache.iotdb.db.query.executor.groupby.SlidingWindowGroupByExecutor
- - org.apache.iotdb.db.query.executor.groupby.impl.EmptyQueueSlidingWindowGroupByExecutor

```
public class EmptyQueueSlidingWindowGroupByExecutor
extends SlidingWindowGroupByExecutor
```
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.

Field Summary
- Fields inherited from class org.apache.iotdb.db.query.executor.groupby.SlidingWindowGroupByExecutor
  aggregateResult, curEndTime, curStartTime, deque

Constructors
Constructor	Description
`EmptyQueueSlidingWindowGroupByExecutor(org.apache.iotdb.tsfile.file.metadata.enums.TSDataType dataType, java.lang.String aggrFuncName, boolean ascending)`

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`evictingExpiredValue()`	evicting expired element in queue and reset expired aggregateResult
`void`	`update(AggregateResult aggregateResult)`	update queue and aggregateResult

Methods inherited from class org.apache.iotdb.db.query.executor.groupby.SlidingWindowGroupByExecutor
getAggregateResult, inTimeRange, setTimeRange

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

Class EmptyQueueSlidingWindowGroupByExecutor