ValueMapperWithKey (kafka 2.8.1 API)

Type Parameters:

K - key type

V - value type

VR - mapped value type
```
public interface ValueMapperWithKey<K,V,VR>
```
The ValueMapperWithKey interface for mapping a value to a new value of arbitrary type. This is a stateless record-by-record operation, i.e, apply(Object, Object) is invoked individually for each record of a stream (cf. ValueTransformer for stateful value transformation). If ValueMapperWithKey is applied to a key-value pair record the record's key is preserved. Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. If a record's key and value should be modified KeyValueMapper can be used.

See Also:

KeyValueMapper, ValueTransformer, ValueTransformerWithKey, KStream.mapValues(ValueMapper), KStream.mapValues(ValueMapperWithKey), KStream.flatMapValues(ValueMapper), KStream.flatMapValues(ValueMapperWithKey), KTable.mapValues(ValueMapper), KTable.mapValues(ValueMapperWithKey)

- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  VR apply(K readOnlyKey, V value)
  Map the given [key and ]value to a new value.

- Method Detail
  - apply
```
VR apply(K readOnlyKey,
         V value)
```
    Map the given [key and ]value to a new value.
    
    Parameters:
    
    readOnlyKey - the read-only key
    
    value - the value to be mapped
    
    Returns:
    
    the new value