Package org.apache.kafka.streams.internals

Class KeyValueStoreFacade<K,V>

java.lang.Object

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

org.apache.kafka.streams.internals.KeyValueStoreFacade<K,V>

All Implemented Interfaces:

StateStore, KeyValueStore<K,V>, ReadOnlyKeyValueStore<K,V>

public class KeyValueStoreFacade<K,V>
extends ReadOnlyKeyValueStoreFacade<K,V>
implements KeyValueStore<K,V>

Field Summary

Fields inherited from class org.apache.kafka.streams.state.internals.ReadOnlyKeyValueStoreFacade

inner

Constructor Summary

Constructors

Constructor	Description
KeyValueStoreFacade(TimestampedKeyValueStore<K,V> inner)

Method Summary

Modifier and Type	Method	Description
void	close()	Close the storage engine.
V	delete(K key)	Delete the value from the store (if there is one).
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
String	name()	The name of this store.
boolean	persistent()	Return if the storage is persistent or not.
void	put(K key, V value)	Update the value associated with this key.
void	putAll(List<KeyValue<K,V>> entries)	Update all the given key/value pairs.
V	putIfAbsent(K key, V value)	Update the value associated with this key, unless a value is already associated with the key.

Methods inherited from class org.apache.kafka.streams.state.internals.ReadOnlyKeyValueStoreFacade

all, approximateNumEntries, get, range

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.kafka.streams.state.ReadOnlyKeyValueStore

all, approximateNumEntries, get, range

Constructor Detail

KeyValueStoreFacade

public KeyValueStoreFacade(TimestampedKeyValueStore<K,V> inner)

Method Detail

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

put

public void put(K key,
                V value)

Description copied from interface: KeyValueStore

Update the value associated with this key.

Specified by:

put in interface KeyValueStore<K,V>

Parameters:

key - The key to associate the value to

value - The value to update, it can be null; if the serialized bytes are also null it is interpreted as deletes

putIfAbsent

public V putIfAbsent(K key,
                     V value)

Description copied from interface: KeyValueStore

Update the value associated with this key, unless a value is already associated with the key.

Specified by:

putIfAbsent in interface KeyValueStore<K,V>

Parameters:

key - The key to associate the value to

value - The value to update, it can be null; if the serialized bytes are also null it is interpreted as deletes

Returns:

The old value or null if there is no such key.

putAll

public void putAll(List<KeyValue<K,V>> entries)

Description copied from interface: KeyValueStore

Update all the given key/value pairs.

Specified by:

putAll in interface KeyValueStore<K,V>

Parameters:

entries - A list of entries to put into the store; if the serialized bytes are also null it is interpreted as deletes

delete

public V delete(K key)

Description copied from interface: KeyValueStore

Delete the value from the store (if there is one).

Specified by:

delete in interface KeyValueStore<K,V>

Parameters:

key - The key

Returns:

The old value or null if there is no such key.

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

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