Package org.apache.kafka.streams.kstream

Interface Initializer<VAgg>

Type Parameters:

VAgg - aggregate value type

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface Initializer<VAgg>

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

See Also:

• Aggregator
• KGroupedStream.aggregate(Initializer, Aggregator)
• KGroupedStream.aggregate(Initializer, Aggregator, Materialized)
• TimeWindowedKStream.aggregate(Initializer, Aggregator)
• TimeWindowedKStream.aggregate(Initializer, Aggregator, Materialized)
• SessionWindowedKStream.aggregate(Initializer, Aggregator, Merger)
• SessionWindowedKStream.aggregate(Initializer, Aggregator, Merger, Materialized)

Method Summary

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

Method Details

apply

VAgg apply()

Return the initial value for an aggregation.

Returns:

the initial value for an aggregation