org.apache.flink.table.runtime.operators.aggregate

Class RecordCounter

java.lang.Object

org.apache.flink.table.runtime.operators.aggregate.RecordCounter

All Implemented Interfaces:

Serializable

public abstract class RecordCounter
extends Object
implements Serializable

The RecordCounter is used to count the number of input records under the current key.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
RecordCounter()

Method Summary

Modifier and Type	Method and Description
static RecordCounter	of(int indexOfCountStar) Creates a RecordCounter depends on the index of count(*).
abstract boolean	recordCountIsZero(RowData acc) We store the counter in the accumulator.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RecordCounter

public RecordCounter()

Method Detail

recordCountIsZero

public abstract boolean recordCountIsZero(RowData acc)

We store the counter in the accumulator. If the counter is not zero, which means we aggregated at least one record for current key.

Returns:

true if input record count is zero, false if not.

of

public static RecordCounter of(int indexOfCountStar)

Creates a RecordCounter depends on the index of count(*). If index is less than zero, returns AccumulationRecordCounter, otherwise, RetractionRecordCounter.

Parameters:

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.