Package org.apache.kafka.streams.state

Class Stores

java.lang.Object

org.apache.kafka.streams.state.Stores

@Evolving
public class Stores
extends java.lang.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.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");
 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Stores.InMemoryKeyValueFactory<K,V>	Deprecated.
static interface	Stores.KeyValueFactory<K,V>
static interface	Stores.PersistentKeyValueFactory<K,V>	Deprecated.
static class	Stores.StoreFactory
static class	Stores.ValueFactory<K>	The factory for creating off-heap key-value stores.

Constructor Summary

Constructors

Constructor	Description
Stores()

Method Summary

Modifier and Type	Method	Description
static Stores.StoreFactory	create(java.lang.String name)	Deprecated. use persistentKeyValueStore(String), persistentWindowStore(String, long, int, long, boolean) persistentSessionStore(String, long), lruMap(String, int), or inMemoryKeyValueStore(String)
static KeyValueBytesStoreSupplier	inMemoryKeyValueStore(java.lang.String name)	Create an in-memory KeyValueBytesStoreSupplier.
static <K,V> StoreBuilder<KeyValueStore<K,V>>	keyValueStoreBuilder(KeyValueBytesStoreSupplier supplier, org.apache.kafka.common.serialization.Serde<K> keySerde, org.apache.kafka.common.serialization.Serde<V> valueSerde)	Creates a StoreBuilder than can be used to build a KeyValueStore.
static KeyValueBytesStoreSupplier	lruMap(java.lang.String name, int maxCacheSize)	Create a LRU Map KeyValueBytesStoreSupplier.
static KeyValueBytesStoreSupplier	persistentKeyValueStore(java.lang.String name)	Create a persistent KeyValueBytesStoreSupplier.
static SessionBytesStoreSupplier	persistentSessionStore(java.lang.String name, long retentionPeriod)	Create a persistent SessionBytesStoreSupplier.
static WindowBytesStoreSupplier	persistentWindowStore(java.lang.String name, long retentionPeriod, int numSegments, long windowSize, boolean retainDuplicates)	Create a persistent WindowBytesStoreSupplier.
static <K,V> StoreBuilder<SessionStore<K,V>>	sessionStoreBuilder(SessionBytesStoreSupplier supplier, org.apache.kafka.common.serialization.Serde<K> keySerde, org.apache.kafka.common.serialization.Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a SessionStore.
static <K,V> StoreBuilder<WindowStore<K,V>>	windowStoreBuilder(WindowBytesStoreSupplier supplier, org.apache.kafka.common.serialization.Serde<K> keySerde, org.apache.kafka.common.serialization.Serde<V> valueSerde)	Creates a StoreBuilder that can be used to build a WindowStore.

Methods inherited from class java.lang.Object

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

Constructor Detail

Stores

public Stores()

Method Detail

persistentKeyValueStore

public static KeyValueBytesStoreSupplier persistentKeyValueStore(java.lang.String name)

Create a persistent KeyValueBytesStoreSupplier.

Parameters:

name - name of the store (cannot be null)

Returns:

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

inMemoryKeyValueStore

public static KeyValueBytesStoreSupplier inMemoryKeyValueStore(java.lang.String name)

Create an in-memory KeyValueBytesStoreSupplier.

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(java.lang.String name,
                                                int maxCacheSize)

Create a LRU Map KeyValueBytesStoreSupplier.

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

persistentWindowStore

public static WindowBytesStoreSupplier persistentWindowStore(java.lang.String name,
                                                             long retentionPeriod,
                                                             int numSegments,
                                                             long windowSize,
                                                             boolean retainDuplicates)

Create a persistent WindowBytesStoreSupplier.

Parameters:

name - name of the store (cannot be null)

retentionPeriod - length of time to retain data in the store (cannot be negative)

numSegments - number of db segments (cannot be zero or negative)

windowSize - size of the windows (cannot be negative)

retainDuplicates - whether or not to retain duplicates.

Returns:

an instance of WindowBytesStoreSupplier

persistentSessionStore

public static SessionBytesStoreSupplier persistentSessionStore(java.lang.String name,
                                                               long retentionPeriod)

Create a persistent SessionBytesStoreSupplier.

Parameters:

name - name of the store (cannot be null)

retentionPeriod - length ot time to retain data in the store (cannot be negative)

Returns:

an instance of a SessionBytesStoreSupplier

windowStoreBuilder

public static <K,V> StoreBuilder<WindowStore<K,V>> windowStoreBuilder(WindowBytesStoreSupplier supplier,
                                                                                  org.apache.kafka.common.serialization.Serde<K> keySerde,
                                                                                  org.apache.kafka.common.serialization.Serde<V> valueSerde)

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

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

keyValueStoreBuilder

public static <K,V> StoreBuilder<KeyValueStore<K,V>> keyValueStoreBuilder(KeyValueBytesStoreSupplier supplier,
                                                                                      org.apache.kafka.common.serialization.Serde<K> keySerde,
                                                                                      org.apache.kafka.common.serialization.Serde<V> valueSerde)

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

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

sessionStoreBuilder

public static <K,V> StoreBuilder<SessionStore<K,V>> sessionStoreBuilder(SessionBytesStoreSupplier supplier,
                                                                                    org.apache.kafka.common.serialization.Serde<K> keySerde,
                                                                                    org.apache.kafka.common.serialization.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

create

@Deprecated
public static Stores.StoreFactory create(java.lang.String name)

Deprecated.

use persistentKeyValueStore(String), persistentWindowStore(String, long, int, long, boolean) persistentSessionStore(String, long), lruMap(String, int), or inMemoryKeyValueStore(String)

Begin to create a new StateStoreSupplier instance.

Parameters:

name - the name of the store

Returns:

the factory that can be used to specify other options or configurations for the store; never null