TopicNameExtractor (kafka 2.8.1 API)

```
public interface TopicNameExtractor<K,V>
```
An interface that allows to dynamically determine the name of the Kafka topic to send at the sink node of the topology.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`String`	`extract(K key, V value, RecordContext recordContext)`	Extracts the topic name to send to.

- Method Detail
  - extract
```
String extract(K key,
               V value,
               RecordContext recordContext)
```
    Extracts the topic name to send to. The topic name must already exist, since the Kafka Streams library will not try to automatically create the topic with the extracted name.
    
    Parameters:
    
    key - the record key
    
    value - the record value
    
    recordContext - current context metadata of the record
    
    Returns:
    
    the topic name this record should be sent to