org.apache.kafka.streams.processor

Interface StateStoreContext

public interface StateStoreContext

State store context interface.

Method Summary

Modifier and Type	Method and Description
Map<String,Object>	appConfigs() Returns all the application config properties as key/value pairs.
Map<String,Object>	appConfigsWithPrefix(String prefix) Returns all the application config properties with the given key prefix, as key/value pairs stripping the prefix.
String	applicationId() Returns the application id.
org.apache.kafka.common.serialization.Serde<?>	keySerde() Returns the default key serde.
StreamsMetrics	metrics() Returns Metrics instance.
Optional<RecordMetadata>	recordMetadata() Return the metadata of the current topic/partition/offset if available.
void	register(StateStore store, StateRestoreCallback stateRestoreCallback) Registers and possibly restores the specified storage engine.
void	register(StateStore store, StateRestoreCallback stateRestoreCallback, CommitCallback commitCallback) Registers and possibly restores the specified storage engine.
File	stateDir() Returns the state directory for the partition.
TaskId	taskId() Returns the task id.
org.apache.kafka.common.serialization.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

recordMetadata

Optional<RecordMetadata> recordMetadata()

Return the metadata of the current topic/partition/offset if available. This is defined as the metadata of the record that is currently being processed (or was last processed) by the StreamTask that holds the store.

Note that the metadata is not defined during all store interactions, for example, while the StreamTask is running a punctuation.

Returns:

metadata of the current record

keySerde

org.apache.kafka.common.serialization.Serde<?> keySerde()

Returns the default key serde.

Returns:

the key serializer

valueSerde

org.apache.kafka.common.serialization.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,
              StateRestoreCallback stateRestoreCallback)

Registers and possibly restores the specified storage engine.

Parameters:

store - the storage engine

stateRestoreCallback - the restoration callback logic for log-backed state stores upon restart

Throws:

IllegalStateException - If store gets registered after initialized is already finished

StreamsException - if the store's change log does not contain the partition

register

@InterfaceStability.Evolving
void register(StateStore store,
                                           StateRestoreCallback stateRestoreCallback,
                                           CommitCallback commitCallback)

Registers and possibly restores the specified storage engine.

Parameters:

store - the storage engine

stateRestoreCallback - the restoration callback logic for log-backed state stores upon restart

commitCallback - a callback to be invoked upon successful task commit, in case the store needs to perform any state tracking when the task is known to be in a consistent state. If the store has no such state to track, it may use register(StateStore, StateRestoreCallback) instead. Persistent stores provided by Kafka Streams use this method to save their Position information to local disk, for example.

Throws:

IllegalStateException - If store gets registered after initialized is already finished

StreamsException - if the store's change log does not contain the partition

appConfigs

Map<String,Object> appConfigs()

Returns all the application config properties as key/value pairs.

The config properties are defined in the StreamsConfig object and associated to the StateStoreContext.

The type of the values is dependent on the type of the property (e.g. the value of DEFAULT_KEY_SERDE_CLASS_CONFIG will be of type Class, even if it was specified as a String to StreamsConfig(Map)).

Returns:

all the key/values from the StreamsConfig properties

appConfigsWithPrefix

Map<String,Object> appConfigsWithPrefix(String prefix)

Returns all the application config properties with the given key prefix, as key/value pairs stripping the prefix.

The config properties are defined in the StreamsConfig object and associated to the StateStoreContext.

Parameters:

prefix - the properties prefix

Returns:

the key/values matching the given prefix from the StreamsConfig properties.