Reducer (kafka 2.8.1 API)

Type Parameters:

V - value type
```
public interface Reducer<V>
```
The Reducer interface for combining two values of the same type into a new value. In contrast to Aggregator the result type must be the same as the input type.
The provided values can be either original values from input KeyValue pair records or be a previously computed result from apply(Object, Object).
Reducer can be used to implement aggregation functions like sum, min, or max.

See Also:

KGroupedStream.reduce(Reducer), KGroupedStream.reduce(Reducer, Materialized), TimeWindowedKStream.reduce(Reducer), TimeWindowedKStream.reduce(Reducer, Materialized), SessionWindowedKStream.reduce(Reducer), SessionWindowedKStream.reduce(Reducer, Materialized), Aggregator

- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  V apply(V value1, V value2)
  Aggregate the two given values into a single one.

- Method Detail
  - apply
```
V apply(V value1,
        V value2)
```
    Aggregate the two given values into a single one.
    
    Parameters:
    
    value1 - the first value for the aggregation
    
    value2 - the second value for the aggregation
    
    Returns:
    
    the aggregated value