org.apache.kafka.streams.state

Interface KeyValueStore<K,V>

Type Parameters:

K - The key type

V - The value type

All Superinterfaces:

ReadOnlyKeyValueStore<K,V>, StateStore

public interface KeyValueStore<K,V>
extends StateStore, ReadOnlyKeyValueStore<K,V>

A key-value store that supports put/get/delete and range queries.

Method Summary

Modifier and Type	Method and Description
V	delete(K key) Delete the value from the store (if there is one).
void	put(K key, V value) Update the value associated with this key.
void	putAll(java.util.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 interface org.apache.kafka.streams.processor.StateStore

close, flush, init, isOpen, name, persistent

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

all, approximateNumEntries, get, range

Method Detail

put

void put(K key,
         V value)

Update the value associated with this key.

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

Throws:

java.lang.NullPointerException - If null is used for key.

putIfAbsent

V putIfAbsent(K key,
              V value)

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

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.

Throws:

java.lang.NullPointerException - If null is used for key.

putAll

void putAll(java.util.List<KeyValue<K,V>> entries)

Update all the given key/value pairs.

Parameters:

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

Throws:

java.lang.NullPointerException - If null is used for key.

delete

V delete(K key)

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

Parameters:

key - The key

Returns:

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

Throws:

java.lang.NullPointerException - If null is used for key.