public abstract class RecordCounter extends Object implements Serializable
RecordCounter
is used to count the number of input records under the current key.Constructor and Description |
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RecordCounter() |
Modifier and Type | Method and Description |
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static RecordCounter |
of(int indexOfCountStar)
Creates a
RecordCounter depends on the index of count(*). |
public static RecordCounter of(int indexOfCountStar)
RecordCounter
depends on the index of count(*).
If index is less than zero, returns AccumulationRecordCounter
,
otherwise, RetractionRecordCounter
.indexOfCountStar
- The index of COUNT(*) in the aggregates.
-1 when the input doesn't contain COUNT(*), i.e. doesn't contain retraction messages.
We make sure there is a COUNT(*) if input stream contains retraction.Copyright © 2014–2020 The Apache Software Foundation. All rights reserved.