org.apache.kafka.streams.kstream

Class Materialized<K,V,S extends StateStore>

java.lang.Object

org.apache.kafka.streams.kstream.Materialized<K,V,S>

Type Parameters:

K - type of record key

V - type of record value

S - type of state store (note: state stores always have key/value types <Bytes,byte[]>

public class Materialized<K,V,S extends StateStore>
extends Object

Used to describe how a StateStore should be materialized. You can either provide a custom StateStore backend through one of the provided methods accepting a supplier or use the default RocksDB backends by providing just a store name.

For example, you can read a topic as KTable and force a state store materialization to access the content via Interactive Queries API:

 StreamsBuilder builder = new StreamsBuilder();
 KTable<Integer, Integer> table = builder.table(
   "topicName",
   Materialized.as("queryable-store-name"));
 

See Also:

Stores

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	cachingEnabled
protected Serde<K>	keySerde
protected boolean	loggingEnabled
protected Duration	retention
protected String	storeName
protected StoreSupplier<S>	storeSupplier
protected Map<String,String>	topicConfig
protected Serde<V>	valueSerde

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Materialized(Materialized<K,V,S> materialized) Copy constructor.

Method Summary

Modifier and Type	Method and Description
static <K,V> Materialized<K,V,KeyValueStore<org.apache.kafka.common.utils.Bytes,byte[]>>	as(KeyValueBytesStoreSupplier supplier) Materialize a KeyValueStore using the provided KeyValueBytesStoreSupplier.
static <K,V> Materialized<K,V,SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>>	as(SessionBytesStoreSupplier supplier) Materialize a SessionStore using the provided SessionBytesStoreSupplier.
static <K,V,S extends StateStore> Materialized<K,V,S>	as(String storeName) Materialize a StateStore with the given name.
static <K,V> Materialized<K,V,WindowStore<org.apache.kafka.common.utils.Bytes,byte[]>>	as(WindowBytesStoreSupplier supplier) Materialize a WindowStore using the provided WindowBytesStoreSupplier.
static <K,V,S extends StateStore> Materialized<K,V,S>	with(Serde<K> keySerde, Serde<V> valueSerde) Materialize a StateStore with the provided key and value Serdes.
Materialized<K,V,S>	withCachingDisabled() Disable caching for the materialized StateStore.
Materialized<K,V,S>	withCachingEnabled() Enable caching for the materialized StateStore.
Materialized<K,V,S>	withKeySerde(Serde<K> keySerde) Set the keySerde the materialize StateStore will use.
Materialized<K,V,S>	withLoggingDisabled() Disable change logging for the materialized StateStore.
Materialized<K,V,S>	withLoggingEnabled(Map<String,String> config) Indicates that a changelog should be created for the store.
Materialized<K,V,S>	withRetention(Duration retention) Configure retention period for window and session stores.
Materialized<K,V,S>	withValueSerde(Serde<V> valueSerde) Set the valueSerde the materialized StateStore will use.

Methods inherited from class java.lang.Object

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

Field Detail

storeSupplier

protected StoreSupplier<S extends StateStore> storeSupplier

storeName

protected String storeName

valueSerde

protected Serde<V> valueSerde

keySerde

protected Serde<K> keySerde

loggingEnabled

protected boolean loggingEnabled

cachingEnabled

protected boolean cachingEnabled

topicConfig

protected Map<String,String> topicConfig

retention

protected Duration retention

Constructor Detail

Materialized

protected Materialized(Materialized<K,V,S> materialized)

Copy constructor.

Parameters:

materialized - the Materialized instance to copy.

Method Detail

as

public static <K,V,S extends StateStore> Materialized<K,V,S> as(String storeName)

Materialize a StateStore with the given name.

Type Parameters:

K - key type of the store

V - value type of the store

S - type of the StateStore

Parameters:

storeName - the name of the underlying KTable state store; valid characters are ASCII alphanumerics, '.', '_' and '-'.

Returns:

a new Materialized instance with the given storeName

as

public static <K,V> Materialized<K,V,WindowStore<org.apache.kafka.common.utils.Bytes,byte[]>> as(WindowBytesStoreSupplier supplier)

Materialize a WindowStore using the provided WindowBytesStoreSupplier. Important: Custom subclasses are allowed here, but they should respect the retention contract: Window stores are required to retain windows at least as long as (window size + window grace period). Stores constructed via Stores already satisfy this contract.

Type Parameters:

K - key type of the store

V - value type of the store

Parameters:

supplier - the WindowBytesStoreSupplier used to materialize the store

Returns:

a new Materialized instance with the given supplier

as

public static <K,V> Materialized<K,V,SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>> as(SessionBytesStoreSupplier supplier)

Materialize a SessionStore using the provided SessionBytesStoreSupplier. Important: Custom subclasses are allowed here, but they should respect the retention contract: Session stores are required to retain windows at least as long as (session inactivity gap + session grace period). Stores constructed via Stores already satisfy this contract.

Type Parameters:

K - key type of the store

V - value type of the store

Parameters:

supplier - the SessionBytesStoreSupplier used to materialize the store

Returns:

a new Materialized instance with the given sup plier

as

public static <K,V> Materialized<K,V,KeyValueStore<org.apache.kafka.common.utils.Bytes,byte[]>> as(KeyValueBytesStoreSupplier supplier)

Materialize a KeyValueStore using the provided KeyValueBytesStoreSupplier.

Type Parameters:

K - key type of the store

V - value type of the store

Parameters:

supplier - the KeyValueBytesStoreSupplier used to materialize the store

Returns:

a new Materialized instance with the given supplier

with

public static <K,V,S extends StateStore> Materialized<K,V,S> with(Serde<K> keySerde,
                                                                  Serde<V> valueSerde)

Materialize a StateStore with the provided key and value Serdes. An internal name will be used for the store.

Type Parameters:

K - key type

V - value type

S - store type

Parameters:

keySerde - the key Serde to use. If the Serde is null, then the default key serde from configs will be used

valueSerde - the value Serde to use. If the Serde is null, then the default value serde from configs will be used

Returns:

a new Materialized instance with the given key and value serdes

withValueSerde

public Materialized<K,V,S> withValueSerde(Serde<V> valueSerde)

Set the valueSerde the materialized StateStore will use.

Parameters:

valueSerde - the value Serde to use. If the Serde is null, then the default value serde from configs will be used. If the serialized bytes is null for put operations, it is treated as delete operation

Returns:

itself

withKeySerde

public Materialized<K,V,S> withKeySerde(Serde<K> keySerde)

Set the keySerde the materialize StateStore will use.

Parameters:

keySerde - the key Serde to use. If the Serde is null, then the default key serde from configs will be used

Returns:

itself

withLoggingEnabled

public Materialized<K,V,S> withLoggingEnabled(Map<String,String> config)

Indicates that a changelog should be created for the store. The changelog will be created with the provided configs.

Note: Any unrecognized configs will be ignored.

Parameters:

config - any configs that should be applied to the changelog

Returns:

itself

withLoggingDisabled

public Materialized<K,V,S> withLoggingDisabled()

Disable change logging for the materialized StateStore.

Returns:

itself

withCachingEnabled

public Materialized<K,V,S> withCachingEnabled()

Enable caching for the materialized StateStore.

Returns:

itself

withCachingDisabled

public Materialized<K,V,S> withCachingDisabled()

Disable caching for the materialized StateStore.

Returns:

itself

withRetention

public Materialized<K,V,S> withRetention(Duration retention)
                                  throws IllegalArgumentException

Configure retention period for window and session stores. Ignored for key/value stores. Overridden by pre-configured store suppliers (as(SessionBytesStoreSupplier) or as(WindowBytesStoreSupplier)). 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.

Parameters:

retention - the retention time

Returns:

itself

Throws:

IllegalArgumentException - if retention is negative or can't be represented as long milliseconds