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.