org.apache.kafka.streams.kstream

Interface Initializer<VA>

Type Parameters:

VA - aggregate value type

public interface Initializer<VA>

The Initializer interface for creating an initial value in aggregations. Initializer is used in combination with Aggregator.

See Also:

Aggregator, KGroupedStream.aggregate(Initializer, Aggregator, org.apache.kafka.common.serialization.Serde, String), KGroupedStream.aggregate(Initializer, Aggregator, org.apache.kafka.streams.processor.StateStoreSupplier), KGroupedStream.aggregate(Initializer, Aggregator, Windows, org.apache.kafka.common.serialization.Serde, String), KGroupedStream.aggregate(Initializer, Aggregator, Windows, org.apache.kafka.streams.processor.StateStoreSupplier), KGroupedStream.aggregate(Initializer, Aggregator, Merger, SessionWindows, org.apache.kafka.common.serialization.Serde, String), KGroupedStream.aggregate(Initializer, Aggregator, Merger, SessionWindows, org.apache.kafka.common.serialization.Serde, org.apache.kafka.streams.processor.StateStoreSupplier)

Method Summary

Modifier and Type	Method and Description
VA	apply() Return the initial value for an aggregation.

Method Detail

apply

VA apply()

Return the initial value for an aggregation.

Returns:

the initial value for an aggregation