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

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Materialized.StoreType

Field Summary

Fields

Modifier and Type	Field and Description
Materialized.StoreType	storeType

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,S extends StateStore> Materialized<K,V,S>	as(Materialized.StoreType storeType) Materialize a StateStore with the given Materialized.StoreType.
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(org.apache.kafka.common.serialization.Serde<K> keySerde, org.apache.kafka.common.serialization.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(org.apache.kafka.common.serialization.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>	withStoreType(Materialized.StoreType storeType) Set the type of the materialized StateStore.
Materialized<K,V,S>	withValueSerde(org.apache.kafka.common.serialization.Serde<V> valueSerde) Set the valueSerde the materialized StateStore will use.

Methods inherited from class java.lang.Object

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

Field Detail

storeType

public Materialized.StoreType storeType

Method Detail

as

public static <K,V,S extends StateStore> Materialized<K,V,S> as(Materialized.StoreType storeType)

Materialize a StateStore with the given Materialized.StoreType.

Type Parameters:

K - key type of the store

V - value type of the store

S - type of the StateStore

Parameters:

storeType - the type of the state store

Returns:

a new Materialized instance with the given storeName

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(org.apache.kafka.common.serialization.Serde<K> keySerde,
                                                                  org.apache.kafka.common.serialization.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(org.apache.kafka.common.serialization.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(org.apache.kafka.common.serialization.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. If not specified, the retention period would be set as the window length (from window-start through window-end) plus the grace period.

Parameters:

retention - the retention time

Returns:

itself

Throws:

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

withStoreType

public Materialized<K,V,S> withStoreType(Materialized.StoreType storeType)
                                  throws IllegalArgumentException

Set the type of the materialized StateStore.

Parameters:

storeType - the store type Materialized.StoreType to use.

Returns:

itself

Throws:

IllegalArgumentException - if store supplier is also pre-configured