org.apache.kafka.streams.processor

Interface ProcessorContext

@InterfaceStability.Unstable
public interface ProcessorContext

Processor context interface.

Method Summary

Methods

Modifier and Type	Method and Description
String	applicationId() Returns the application id
void	commit() Requests a commit
<K,V> void	forward(K key, V value) Forwards a key/value pair to the downstream processors
<K,V> void	forward(K key, V value, int childIndex) Forwards a key/value pair to one of the downstream processors designated by childIndex
<K,V> void	forward(K key, V value, String childName) Forwards a key/value pair to one of the downstream processors designated by the downstream processor name
StateStore	getStateStore(String name) Get the state store given the store name.
Serde<?>	keySerde() Returns the default key serde
StreamsMetrics	metrics() Returns Metrics instance
long	offset() Returns the offset of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call)
int	partition() Returns the partition id of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call)
void	register(StateStore store, boolean loggingEnabled, StateRestoreCallback stateRestoreCallback) Registers and possibly restores the specified storage engine.
void	schedule(long interval) Schedules a periodic operation for processors.
File	stateDir() Returns the state directory for the partition.
TaskId	taskId() Returns the task id
long	timestamp() Returns the current timestamp.
String	topic() Returns the topic name of the current input record; could be null if it is not available (for example, if this method is invoked from the punctuate call)
Serde<?>	valueSerde() Returns the default value serde

Method Detail

applicationId

String applicationId()

Returns the application id

Returns:

the application id

taskId

TaskId taskId()

Returns the task id

Returns:

the task id

keySerde

Serde<?> keySerde()

Returns the default key serde

Returns:

the key serializer

valueSerde

Serde<?> valueSerde()

Returns the default value serde

Returns:

the value serializer

stateDir

File stateDir()

Returns the state directory for the partition.

Returns:

the state directory

metrics

StreamsMetrics metrics()

Returns Metrics instance

Returns:

StreamsMetrics

register

void register(StateStore store,
            boolean loggingEnabled,
            StateRestoreCallback stateRestoreCallback)

Registers and possibly restores the specified storage engine.

Parameters:

store - the storage engine

getStateStore

StateStore getStateStore(String name)

Get the state store given the store name.

Parameters:

name - The store name

Returns:

The state store instance

schedule

void schedule(long interval)

Schedules a periodic operation for processors. A processor may call this method during initialization to schedule a periodic call called a punctuation to Processor.punctuate(long).

Parameters:

interval - the time interval between punctuations

forward

<K,V> void forward(K key,
                 V value)

Forwards a key/value pair to the downstream processors

Parameters:

key - key

value - value

forward

<K,V> void forward(K key,
                 V value,
                 int childIndex)

Forwards a key/value pair to one of the downstream processors designated by childIndex

Parameters:

key - key

value - value

childIndex - index in list of children of this node

forward

<K,V> void forward(K key,
                 V value,
                 String childName)

Forwards a key/value pair to one of the downstream processors designated by the downstream processor name

Parameters:

key - key

value - value

childName - name of downstream processor

commit

void commit()

Requests a commit

topic

String topic()

Returns the topic name of the current input record; could be null if it is not available (for example, if this method is invoked from the punctuate call)

Returns:

the topic name

partition

int partition()

Returns the partition id of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call)

Returns:

the partition id

offset

long offset()

Returns the offset of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call)

Returns:

the offset

timestamp

long timestamp()

Returns the current timestamp. If it is triggered while processing a record streamed from the source processor, timestamp is defined as the timestamp of the current input record; the timestamp is extracted from ConsumerRecord by TimestampExtractor. If it is triggered while processing a record generated not from the source processor (for example, if this method is invoked from the punctuate call), timestamp is defined as the current task's stream time, which is defined as the smallest among all its input stream partition timestamps.

Returns:

the timestamp