Class Stores

java.lang.Object

org.apache.kafka.streams.state.Stores

public final class Stores
extends Object

Factory for creating state stores in Kafka Streams.

When using the high-level DSL, i.e., StreamsBuilder, users create StoreSuppliers that can be further customized via Materialized. For example, a topic read as KTable can be materialized into an in-memory store with custom key/value serdes and caching disabled:

StreamsBuilder builder = new StreamsBuilder();
KeyValueBytesStoreSupplier storeSupplier = Stores.inMemoryKeyValueStore("queryable-store-name");
KTable<Long,String> table = builder.table(
  "topicName",
  Materialized.<Long,String>as(storeSupplier)
              .withKeySerde(Serdes.Long())
              .withValueSerde(Serdes.String())
              .withCachingDisabled());

When using the Processor API, i.e., Topology, users create StoreBuilders that can be attached to Processors. For example, you can create a windowed RocksDB store with custom changelog topic configuration like:

Topology topology = new Topology();
topology.addProcessor("processorName", ...);

Map<String,String> topicConfig = new HashMap<>();
StoreBuilder<WindowStore<Integer, Long>> storeBuilder = Stores
  .windowStoreBuilder(
    Stores.persistentWindowStore("queryable-store-name", ...),
    Serdes.Integer(),
    Serdes.Long())
  .withLoggingEnabled(topicConfig);

topology.addStateStore(storeBuilder, "processorName");

Constructor Summary

Constructors

Constructor	Description
Stores()

Method Summary

Modifier and Type	Method	Description
static KeyValueBytesStoreSupplier	inMemoryKeyValueStore(String name)	Create an in-memory KeyValueBytesStoreSupplier.
static SessionBytesStoreSupplier	inMemorySessionStore(String name, Duration retentionPeriod)	Create an in-memory SessionBytesStoreSupplier.
static WindowBytesStoreSupplier	inMemoryWindowStore(String name, Duration retentionPeriod, Duration windowSize, boolean retainDuplicates)	Create an in-memory WindowBytesStoreSupplier.
static <K,V> StoreBuilder<KeyValueStore<K,V>>	keyValueStoreBuilder(KeyValueBytesStoreSupplier supplier, Serde<K> keySerde, Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a KeyValueStore.
static KeyValueBytesStoreSupplier	lruMap(String name, int maxCacheSize)	Create a LRU Map KeyValueBytesStoreSupplier.
static KeyValueBytesStoreSupplier	persistentKeyValueStore(String name)	Create a persistent KeyValueBytesStoreSupplier.
static SessionBytesStoreSupplier	persistentSessionStore(String name, Duration retentionPeriod)	Create a persistent SessionBytesStoreSupplier.
static KeyValueBytesStoreSupplier	persistentTimestampedKeyValueStore(String name)	Create a persistent KeyValueBytesStoreSupplier.
static WindowBytesStoreSupplier	persistentTimestampedWindowStore(String name, Duration retentionPeriod, Duration windowSize, boolean retainDuplicates)	Create a persistent WindowBytesStoreSupplier.
static VersionedBytesStoreSupplier	persistentVersionedKeyValueStore(String name, Duration historyRetention)	Create a persistent versioned key-value store VersionedBytesStoreSupplier.
static VersionedBytesStoreSupplier	persistentVersionedKeyValueStore(String name, Duration historyRetention, Duration segmentInterval)	Create a persistent versioned key-value store VersionedBytesStoreSupplier.
static WindowBytesStoreSupplier	persistentWindowStore(String name, Duration retentionPeriod, Duration windowSize, boolean retainDuplicates)	Create a persistent WindowBytesStoreSupplier.
static <K,V> StoreBuilder<SessionStore<K,V>>	sessionStoreBuilder(SessionBytesStoreSupplier supplier, Serde<K> keySerde, Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a SessionStore.
static <K,V> StoreBuilder<TimestampedKeyValueStore<K,V>>	timestampedKeyValueStoreBuilder(KeyValueBytesStoreSupplier supplier, Serde<K> keySerde, Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a TimestampedKeyValueStore.
static <K,V> StoreBuilder<TimestampedWindowStore<K,V>>	timestampedWindowStoreBuilder(WindowBytesStoreSupplier supplier, Serde<K> keySerde, Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a TimestampedWindowStore.
static <K,V> StoreBuilder<VersionedKeyValueStore<K,V>>	versionedKeyValueStoreBuilder(VersionedBytesStoreSupplier supplier, Serde<K> keySerde, Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a VersionedKeyValueStore.
static <K,V> StoreBuilder<WindowStore<K,V>>	windowStoreBuilder(WindowBytesStoreSupplier supplier, Serde<K> keySerde, Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a WindowStore.

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Stores

public Stores()

Method Details

persistentKeyValueStore

public static KeyValueBytesStoreSupplier persistentKeyValueStore(String name)

Create a persistent KeyValueBytesStoreSupplier.

This store supplier can be passed into a keyValueStoreBuilder(KeyValueBytesStoreSupplier, Serde, Serde). If you want to create a TimestampedKeyValueStore or VersionedKeyValueStore you should use persistentTimestampedKeyValueStore(String) or persistentVersionedKeyValueStore(String, Duration), respectively, to create a store supplier instead.

Parameters:

name - name of the store (cannot be null)

Returns:

an instance of a KeyValueBytesStoreSupplier that can be used to build a persistent key-value store

persistentTimestampedKeyValueStore

public static KeyValueBytesStoreSupplier persistentTimestampedKeyValueStore(String name)

Create a persistent KeyValueBytesStoreSupplier.

This store supplier can be passed into a timestampedKeyValueStoreBuilder(KeyValueBytesStoreSupplier, Serde, Serde). If you want to create a KeyValueStore or a VersionedKeyValueStore you should use persistentKeyValueStore(String) or persistentVersionedKeyValueStore(String, Duration), respectively, to create a store supplier instead.

Parameters:

name - name of the store (cannot be null)

Returns:

an instance of a KeyValueBytesStoreSupplier that can be used to build a persistent key-(timestamp/value) store

persistentVersionedKeyValueStore

public static VersionedBytesStoreSupplier persistentVersionedKeyValueStore(String name,
 Duration historyRetention)

Create a persistent versioned key-value store VersionedBytesStoreSupplier.

This store supplier can be passed into a versionedKeyValueStoreBuilder(VersionedBytesStoreSupplier, Serde, Serde).

Note that it is not safe to change the value of historyRetention between application restarts without clearing local state from application instances, as this may cause incorrect values to be read from the state store if it impacts the underlying storage format.

Parameters:

name - name of the store (cannot be null)

historyRetention - length of time that old record versions are available for query (cannot be negative). If a timestamp bound provided to VersionedKeyValueStore.get(Object, long) is older than this specified history retention, then the get operation will not return data. This parameter also determines the "grace period" after which out-of-order writes will no longer be accepted.

Returns:

an instance of VersionedBytesStoreSupplier

Throws:

IllegalArgumentException - if historyRetention can't be represented as long milliseconds

persistentVersionedKeyValueStore

public static VersionedBytesStoreSupplier persistentVersionedKeyValueStore(String name,
 Duration historyRetention,
 Duration segmentInterval)

Create a persistent versioned key-value store VersionedBytesStoreSupplier.

This store supplier can be passed into a versionedKeyValueStoreBuilder(VersionedBytesStoreSupplier, Serde, Serde).

Note that it is not safe to change the value of segmentInterval between application restarts without clearing local state from application instances, as this may cause incorrect values to be read from the state store otherwise.

Parameters:

name - name of the store (cannot be null)

historyRetention - length of time that old record versions are available for query (cannot be negative). If a timestamp bound provided to VersionedKeyValueStore.get(Object, long) is older than this specified history retention, then the get operation will not return data. This parameter also determines the "grace period" after which out-of-order writes will no longer be accepted.

segmentInterval - size of segments for storing old record versions (must be positive). Old record versions for the same key in a single segment are stored (updated and accessed) together. The only impact of this parameter is performance. If segments are large and a workload results in many record versions for the same key being collected in a single segment, performance may degrade as a result. On the other hand, historical reads (which access older segments) and out-of-order writes may slow down if there are too many segments.

Returns:

an instance of VersionedBytesStoreSupplier

Throws:

IllegalArgumentException - if historyRetention or segmentInterval can't be represented as long milliseconds

inMemoryKeyValueStore

public static KeyValueBytesStoreSupplier inMemoryKeyValueStore(String name)

Create an in-memory KeyValueBytesStoreSupplier.

This store supplier can be passed into a keyValueStoreBuilder(KeyValueBytesStoreSupplier, Serde, Serde) or timestampedKeyValueStoreBuilder(KeyValueBytesStoreSupplier, Serde, Serde).

Parameters:

name - name of the store (cannot be null)

Returns:

an instance of a KeyValueBytesStoreSupplier than can be used to build an in-memory store

lruMap

public static KeyValueBytesStoreSupplier lruMap(String name,
 int maxCacheSize)

Create a LRU Map KeyValueBytesStoreSupplier.

This store supplier can be passed into a keyValueStoreBuilder(KeyValueBytesStoreSupplier, Serde, Serde) or timestampedKeyValueStoreBuilder(KeyValueBytesStoreSupplier, Serde, Serde).

Parameters:

name - name of the store (cannot be null)

maxCacheSize - maximum number of items in the LRU (cannot be negative)

Returns:

an instance of a KeyValueBytesStoreSupplier that can be used to build an LRU Map based store

Throws:

IllegalArgumentException - if maxCacheSize is negative

persistentWindowStore

public static WindowBytesStoreSupplier persistentWindowStore(String name,
 Duration retentionPeriod,
 Duration windowSize,
 boolean retainDuplicates)
                                                      throws IllegalArgumentException

Create a persistent WindowBytesStoreSupplier.

This store supplier can be passed into a windowStoreBuilder(WindowBytesStoreSupplier, Serde, Serde). If you want to create a TimestampedWindowStore you should use persistentTimestampedWindowStore(String, Duration, Duration, boolean) to create a store supplier instead.

Note that it is not safe to change the value of retentionPeriod between application restarts without clearing local state from application instances, as this may cause incorrect values to be read from the state store if it impacts the underlying storage format.

Parameters:

name - name of the store (cannot be null)

retentionPeriod - length of time to retain data in the store (cannot be negative) (note that the retention period must be at least long enough to contain the windowed data's entire life cycle, from window-start through window-end, and for the entire grace period)

windowSize - size of the windows (cannot be negative)

retainDuplicates - whether or not to retain duplicates. Turning this on will automatically disable caching and means that null values will be ignored.

Returns:

an instance of WindowBytesStoreSupplier

Throws:

IllegalArgumentException - if retentionPeriod or windowSize can't be represented as long milliseconds

IllegalArgumentException - if retentionPeriod is smaller than windowSize

persistentTimestampedWindowStore

public static WindowBytesStoreSupplier persistentTimestampedWindowStore(String name,
 Duration retentionPeriod,
 Duration windowSize,
 boolean retainDuplicates)
                                                                 throws IllegalArgumentException

Create a persistent WindowBytesStoreSupplier.

This store supplier can be passed into a timestampedWindowStoreBuilder(WindowBytesStoreSupplier, Serde, Serde). If you want to create a WindowStore you should use persistentWindowStore(String, Duration, Duration, boolean) to create a store supplier instead.

Note that it is not safe to change the value of retentionPeriod between application restarts without clearing local state from application instances, as this may cause incorrect values to be read from the state store if it impacts the underlying storage format.

Parameters:

name - name of the store (cannot be null)

retentionPeriod - length of time to retain data in the store (cannot be negative) (note that the retention period must be at least long enough to contain the windowed data's entire life cycle, from window-start through window-end, and for the entire grace period)

windowSize - size of the windows (cannot be negative)

retainDuplicates - whether or not to retain duplicates. Turning this on will automatically disable caching and means that null values will be ignored.

Returns:

an instance of WindowBytesStoreSupplier

Throws:

IllegalArgumentException - if retentionPeriod or windowSize can't be represented as long milliseconds

IllegalArgumentException - if retentionPeriod is smaller than windowSize

inMemoryWindowStore

public static WindowBytesStoreSupplier inMemoryWindowStore(String name,
 Duration retentionPeriod,
 Duration windowSize,
 boolean retainDuplicates)
                                                    throws IllegalArgumentException

Create an in-memory WindowBytesStoreSupplier.

This store supplier can be passed into a windowStoreBuilder(WindowBytesStoreSupplier, Serde, Serde) or timestampedWindowStoreBuilder(WindowBytesStoreSupplier, Serde, Serde).

Parameters:

name - name of the store (cannot be null)

retentionPeriod - length of time to retain data in the store (cannot be negative) Note that the retention period must be at least long enough to contain the windowed data's entire life cycle, from window-start through window-end, and for the entire grace period.

windowSize - size of the windows (cannot be negative)

retainDuplicates - whether or not to retain duplicates. Turning this on will automatically disable caching and means that null values will be ignored.

Returns:

an instance of WindowBytesStoreSupplier

Throws:

IllegalArgumentException - if retentionPeriod or windowSize can't be represented as long milliseconds

IllegalArgumentException - if retentionPeriod is smaller than windowSize

persistentSessionStore

public static SessionBytesStoreSupplier persistentSessionStore(String name,
 Duration retentionPeriod)

Create a persistent SessionBytesStoreSupplier.

Note that it is not safe to change the value of retentionPeriod between application restarts without clearing local state from application instances, as this may cause incorrect values to be read from the state store if it impacts the underlying storage format.

Parameters:

name - name of the store (cannot be null)

retentionPeriod - length of time to retain data in the store (cannot be negative) (note that the retention period must be at least as long enough to contain the inactivity gap of the session and the entire grace period.)

Returns:

an instance of a SessionBytesStoreSupplier

inMemorySessionStore

public static SessionBytesStoreSupplier inMemorySessionStore(String name,
 Duration retentionPeriod)

Create an in-memory SessionBytesStoreSupplier.

Parameters:

name - name of the store (cannot be null)

retentionPeriod - length of time to retain data in the store (cannot be negative) (note that the retention period must be at least as long enough to contain the inactivity gap of the session and the entire grace period.)

Returns:

an instance of a SessionBytesStoreSupplier

keyValueStoreBuilder

public static <K,V>
StoreBuilder<KeyValueStore<K,V>> keyValueStoreBuilder(KeyValueBytesStoreSupplier supplier,
 Serde<K> keySerde,
 Serde<V> valueSerde)

Creates a StoreBuilder that can be used to build a KeyValueStore.

The provided supplier should not be a supplier for TimestampedKeyValueStores.

Type Parameters:

K - key type

V - value type

Parameters:

supplier - a KeyValueBytesStoreSupplier (cannot be null)

keySerde - the key serde to use

valueSerde - the value serde to use; if the serialized bytes is null for put operations, it is treated as delete

Returns:

an instance of a StoreBuilder that can build a KeyValueStore

timestampedKeyValueStoreBuilder

public static <K,V>
StoreBuilder<TimestampedKeyValueStore<K,V>> timestampedKeyValueStoreBuilder(KeyValueBytesStoreSupplier supplier,
 Serde<K> keySerde,
 Serde<V> valueSerde)

Creates a StoreBuilder that can be used to build a TimestampedKeyValueStore.

The provided supplier should not be a supplier for KeyValueStores. For this case, passed in timestamps will be dropped and not stored in the key-value-store. On read, no valid timestamp but a dummy timestamp will be returned.

Type Parameters:

K - key type

V - value type

Parameters:

supplier - a KeyValueBytesStoreSupplier (cannot be null)

keySerde - the key serde to use

valueSerde - the value serde to use; if the serialized bytes is null for put operations, it is treated as delete

Returns:

an instance of a StoreBuilder that can build a KeyValueStore

versionedKeyValueStoreBuilder

public static <K,V>
StoreBuilder<VersionedKeyValueStore<K,V>> versionedKeyValueStoreBuilder(VersionedBytesStoreSupplier supplier,
 Serde<K> keySerde,
 Serde<V> valueSerde)

Creates a StoreBuilder that can be used to build a VersionedKeyValueStore.

Type Parameters:

K - key type

V - value type

Parameters:

supplier - a VersionedBytesStoreSupplier (cannot be null)

keySerde - the key serde to use

valueSerde - the value serde to use; if the serialized bytes is null for put operations, it is treated as a deletion

Returns:

an instance of a StoreBuilder that can build a VersionedKeyValueStore

windowStoreBuilder

public static <K,V> StoreBuilder<WindowStore<K,V>> windowStoreBuilder(WindowBytesStoreSupplier supplier,
 Serde<K> keySerde,
 Serde<V> valueSerde)

Creates a StoreBuilder that can be used to build a WindowStore.

The provided supplier should not be a supplier for TimestampedWindowStores.

Type Parameters:

K - key type

V - value type

Parameters:

supplier - a WindowBytesStoreSupplier (cannot be null)

keySerde - the key serde to use

valueSerde - the value serde to use; if the serialized bytes is null for put operations, it is treated as delete

Returns:

an instance of StoreBuilder than can build a WindowStore

timestampedWindowStoreBuilder

public static <K,V>
StoreBuilder<TimestampedWindowStore<K,V>> timestampedWindowStoreBuilder(WindowBytesStoreSupplier supplier,
 Serde<K> keySerde,
 Serde<V> valueSerde)

Creates a StoreBuilder that can be used to build a TimestampedWindowStore.

The provided supplier should not be a supplier for WindowStores. For this case, passed in timestamps will be dropped and not stored in the window-store. On read, no valid timestamp but a dummy timestamp will be returned.

Type Parameters:

K - key type

V - value type

Parameters:

supplier - a WindowBytesStoreSupplier (cannot be null)

keySerde - the key serde to use

valueSerde - the value serde to use; if the serialized bytes is null for put operations, it is treated as delete

Returns:

an instance of StoreBuilder that can build a TimestampedWindowStore

sessionStoreBuilder

public static <K,V> StoreBuilder<SessionStore<K,V>> sessionStoreBuilder(SessionBytesStoreSupplier supplier,
 Serde<K> keySerde,
 Serde<V> valueSerde)

Creates a StoreBuilder that can be used to build a SessionStore.

Type Parameters:

K - key type

V - value type

Parameters:

supplier - a SessionBytesStoreSupplier (cannot be null)

keySerde - the key serde to use

valueSerde - the value serde to use; if the serialized bytes is null for put operations, it is treated as delete

Returns:

an instance of StoreBuilder than can build a SessionStore