Package org.apache.kafka.streams.state.internals

Class WrappedStateStore<S extends StateStore,K,V>

java.lang.Object

org.apache.kafka.streams.state.internals.WrappedStateStore<S,K,V>

All Implemented Interfaces:

StateStore, CachedStateStore<K,V>

Direct Known Subclasses:

CachingKeyValueStore, ChangeLoggingKeyValueBytesStore, MeteredKeyValueStore, MeteredSessionStore, MeteredWindowStore, RocksDBSessionStore, RocksDBWindowStore

public abstract class WrappedStateStore<S extends StateStore,K,V>
extends Object
implements StateStore, CachedStateStore<K,V>

A storage engine wrapper for utilities like logging, caching, and metering.

Constructor Summary

Constructors

Constructor	Description
WrappedStateStore(S wrapped)

Method Summary

Modifier and Type	Method	Description
void	close()	Close the storage engine.
void	flush()	Flush any cached data
void	init(ProcessorContext context, StateStore root)	Initializes this state store.
boolean	isOpen()	Is this store open for reading and writing
static boolean	isTimestamped(StateStore stateStore)
String	name()	The name of this store.
boolean	persistent()	Return if the storage is persistent or not.
boolean	setFlushListener(CacheFlushListener<K,V> listener, boolean sendOldValues)	Set the CacheFlushListener to be notified when entries are flushed from the cache to the underlying StateStore
S	wrapped()

Methods inherited from class java.lang.Object

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

Constructor Detail

WrappedStateStore

public WrappedStateStore(S wrapped)

Method Detail

isTimestamped

public static boolean isTimestamped(StateStore stateStore)

init

public void init(ProcessorContext context,
                 StateStore root)

Description copied from interface: StateStore

Initializes this state store.

The implementation of this function must register the root store in the context via the ProcessorContext.register(StateStore, StateRestoreCallback) function, where the first StateStore parameter should always be the passed-in root object, and the second parameter should be an object of user's implementation of the StateRestoreCallback interface used for restoring the state store from the changelog.

Note that if the state store engine itself supports bulk writes, users can implement another interface BatchingStateRestoreCallback which extends StateRestoreCallback to let users implement bulk-load restoration logic instead of restoring one record at a time.

Specified by:

init in interface StateStore

setFlushListener

public boolean setFlushListener(CacheFlushListener<K,V> listener,
                                boolean sendOldValues)

Description copied from interface: CachedStateStore

Set the CacheFlushListener to be notified when entries are flushed from the cache to the underlying StateStore

Specified by:

setFlushListener in interface CachedStateStore<S extends StateStore,K>

name

public String name()

Description copied from interface: StateStore

The name of this store.

Specified by:

name in interface StateStore

Returns:

the storage name

persistent

public boolean persistent()

Description copied from interface: StateStore

Return if the storage is persistent or not.

Specified by:

persistent in interface StateStore

Returns:

true if the storage is persistent—false otherwise

isOpen

public boolean isOpen()

Description copied from interface: StateStore

Is this store open for reading and writing

Specified by:

isOpen in interface StateStore

Returns:

true if the store is open

flush

public void flush()

Description copied from interface: StateStore

Flush any cached data

Specified by:

flush in interface StateStore

close

public void close()

Description copied from interface: StateStore

Close the storage engine. Note that this function needs to be idempotent since it may be called several times on the same state store.

Users only need to implement this function but should NEVER need to call this api explicitly as it will be called by the library automatically when necessary

Specified by:

close in interface StateStore

wrapped

public S wrapped()