org.apache.kafka.streams.processor

Interface Processor<K,V>

Type Parameters:

K - the type of keys

V - the type of values

All Known Implementing Classes:

AbstractProcessor

@InterfaceStability.Evolving
public interface Processor<K,V>

A processor of key-value pair records.

Method Summary

Modifier and Type	Method and Description
void	close() Close this processor and clean up any resources.
void	init(ProcessorContext context) Initialize this processor with the given context.
void	process(K key, V value) Process the record with the given key and value.

Method Detail

init

void init(ProcessorContext context)

Initialize this processor with the given context. The framework ensures this is called once per processor when the topology that contains it is initialized. When the framework is done with the processor, close() will be called on it; the framework may later re-use the processor by calling #init() again.

The provided context can be used to access topology and record meta data, to schedule a method to be called periodically and to access attached StateStores.

Parameters:

context - the context; may not be null

process

void process(K key,
             V value)

Process the record with the given key and value.

Parameters:

key - the key for the record

value - the value for the record

close

void close()

Close this processor and clean up any resources. Be aware that close() is called after an internal cleanup. Thus, it is not possible to write anything to Kafka as underlying clients are already closed. The framework may later re-use this processor by calling #init() on it again.

Note: Do not close any streams managed resources, like StateStores here, as they are managed by the library.