Package org.apache.kafka.streams.kstream
Interface KeyValueMapper<K,V,VR>
-
- Type Parameters:
K
- key typeV
- value typeVR
- mapped value type
public interface KeyValueMapper<K,V,VR>
TheKeyValueMapper
interface for mapping akey-value pair
to a new value of arbitrary type. For example, it can be used to- map from an input
KeyValue
pair to an outputKeyValue
pair with different key and/or value type (for this case output typeVR ==
KeyValue<NewKeyType,NewValueType>
) - map from an input record to a new key (with arbitrary key type as specified by
VR
)
apply(Object, Object)
is invoked individually for each record of a stream (cf.Transformer
for stateful record transformation).KeyValueMapper
is a generalization ofValueMapper
.- See Also:
ValueMapper
,Transformer
,KStream.map(KeyValueMapper)
,KStream.flatMap(KeyValueMapper)
,KStream.selectKey(KeyValueMapper)
,KStream.groupBy(KeyValueMapper)
,KStream.groupBy(KeyValueMapper, Grouped)
,KTable.groupBy(KeyValueMapper)
,KTable.groupBy(KeyValueMapper, Grouped)
,KTable.toStream(KeyValueMapper)
-
-
Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description VR
apply(K key, V value)
Map a record with the given key and value to a new value.
-