org.apache.flink.runtime.state

接口 KeyedStateBackend<K>

类型参数:

K - The key by which state is keyed.

所有超级接口:

org.apache.flink.util.Disposable, KeyedStateFactory, PriorityQueueSetFactory

所有已知子接口:

CheckpointableKeyedStateBackend<K>, TestableKeyedStateBackend<K>

所有已知实现类:

AbstractKeyedStateBackend, HeapKeyedStateBackend

public interface KeyedStateBackend<K>
extends KeyedStateFactory, PriorityQueueSetFactory, org.apache.flink.util.Disposable

A keyed state backend provides methods for managing keyed state.

嵌套类概要

嵌套类

限定符和类型	接口和说明
static interface	KeyedStateBackend.KeySelectionListener<K> Listener is given a callback when setCurrentKey(K) is called (key context changes).

方法概要

限定符和类型	方法和说明
<N,S extends org.apache.flink.api.common.state.State,T> void	applyToAllKeys(N namespace, org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer, org.apache.flink.api.common.state.StateDescriptor<S,T> stateDescriptor, KeyedStateFunction<K,S> function) Applies the provided KeyedStateFunction to the state with the provided StateDescriptor of all the currently active keys.
boolean	deregisterKeySelectionListener(KeyedStateBackend.KeySelectionListener<K> listener) Stop calling listener registered in registerKeySelectionListener(org.apache.flink.runtime.state.KeyedStateBackend.KeySelectionListener<K>).
void	dispose()
K	getCurrentKey()
<N> java.util.stream.Stream<K>	getKeys(String state, N namespace)
<N> java.util.stream.Stream<org.apache.flink.api.java.tuple.Tuple2<K,N>>	getKeysAndNamespaces(String state)
org.apache.flink.api.common.typeutils.TypeSerializer<K>	getKeySerializer()
<N,S extends org.apache.flink.api.common.state.State,T> S	getOrCreateKeyedState(org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer, org.apache.flink.api.common.state.StateDescriptor<S,T> stateDescriptor) Creates or retrieves a keyed state backed by this state backend.
<N,S extends org.apache.flink.api.common.state.State> S	getPartitionedState(N namespace, org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer, org.apache.flink.api.common.state.StateDescriptor<S,?> stateDescriptor) Creates or retrieves a partitioned state backed by this state backend.
default boolean	isSafeToReuseKVState() Whether it's safe to reuse key-values from the state-backend, e.g for the purpose of optimization.
default boolean	isStateImmutableInStateBackend(CheckpointType checkpointOptions) 已过时。
void	registerKeySelectionListener(KeyedStateBackend.KeySelectionListener<K> listener) State backend will call KeyedStateBackend.KeySelectionListener.keySelected(K) when key context is switched if supported.
void	setCurrentKey(K newKey) Sets the current key that is used for partitioned state.

从接口继承的方法 org.apache.flink.runtime.state.KeyedStateFactory

createOrUpdateInternalState, createOrUpdateInternalState, createOrUpdateInternalState

从接口继承的方法 org.apache.flink.runtime.state.PriorityQueueSetFactory

create, create

方法详细资料

setCurrentKey

void setCurrentKey(K newKey)

Sets the current key that is used for partitioned state.

参数:

newKey - The new current key.

getCurrentKey

K getCurrentKey()

返回:

Current key.

getKeySerializer

org.apache.flink.api.common.typeutils.TypeSerializer<K> getKeySerializer()

返回:

Serializer of the key.

applyToAllKeys

<N,S extends org.apache.flink.api.common.state.State,T> void applyToAllKeys(N namespace,
                                                                            org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer,
                                                                            org.apache.flink.api.common.state.StateDescriptor<S,T> stateDescriptor,
                                                                            KeyedStateFunction<K,S> function)
                                                                     throws Exception

Applies the provided KeyedStateFunction to the state with the provided StateDescriptor of all the currently active keys.

类型参数:

N - The type of the namespace.

S - The type of the state.

参数:

namespace - the namespace of the state.

namespaceSerializer - the serializer for the namespace.

stateDescriptor - the descriptor of the state to which the function is going to be applied.

function - the function to be applied to the keyed state.

抛出:

Exception

getKeys

<N> java.util.stream.Stream<K> getKeys(String state,
                                       N namespace)

参数:

state - State variable for which existing keys will be returned.

namespace - Namespace for which existing keys will be returned.

返回:

A stream of all keys for the given state and namespace. Modifications to the state during iterating over it keys are not supported.

getKeysAndNamespaces

<N> java.util.stream.Stream<org.apache.flink.api.java.tuple.Tuple2<K,N>> getKeysAndNamespaces(String state)

参数:

state - State variable for which existing keys will be returned.

返回:

A stream of all keys for the given state and namespace. Modifications to the state during iterating over it keys are not supported. Implementations go not make any ordering guarantees about the returned tupes. Two records with the same key or namespace may not be returned near each other in the stream.

getOrCreateKeyedState

<N,S extends org.apache.flink.api.common.state.State,T> S getOrCreateKeyedState(org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer,
                                                                                org.apache.flink.api.common.state.StateDescriptor<S,T> stateDescriptor)
                                                                         throws Exception

Creates or retrieves a keyed state backed by this state backend.

类型参数:

N - The type of the namespace.

S - The type of the state.

参数:

namespaceSerializer - The serializer used for the namespace type of the state

stateDescriptor - The identifier for the state. This contains name and can create a default state value.

返回:

A new key/value state backed by this backend.

抛出:

Exception - Exceptions may occur during initialization of the state and should be forwarded.

getPartitionedState

<N,S extends org.apache.flink.api.common.state.State> S getPartitionedState(N namespace,
                                                                            org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer,
                                                                            org.apache.flink.api.common.state.StateDescriptor<S,?> stateDescriptor)
                                                                     throws Exception

Creates or retrieves a partitioned state backed by this state backend.

TODO: NOTE: This method does a lot of work caching / retrieving states just to update the namespace. This method should be removed for the sake of namespaces being lazily fetched from the keyed state backend, or being set on the state directly.

类型参数:

N - The type of the namespace.

S - The type of the state.

参数:

stateDescriptor - The identifier for the state. This contains name and can create a default state value.

返回:

A new key/value state backed by this backend.

抛出:

Exception - Exceptions may occur during initialization of the state and should be forwarded.

dispose

void dispose()

指定者:

dispose 在接口中 org.apache.flink.util.Disposable

registerKeySelectionListener

void registerKeySelectionListener(KeyedStateBackend.KeySelectionListener<K> listener)

State backend will call KeyedStateBackend.KeySelectionListener.keySelected(K) when key context is switched if supported.

deregisterKeySelectionListener

boolean deregisterKeySelectionListener(KeyedStateBackend.KeySelectionListener<K> listener)

Stop calling listener registered in registerKeySelectionListener(org.apache.flink.runtime.state.KeyedStateBackend.KeySelectionListener<K>).

返回:

returns true iff listener was registered before.

isStateImmutableInStateBackend

@Deprecated
default boolean isStateImmutableInStateBackend(CheckpointType checkpointOptions)

已过时。

isSafeToReuseKVState

default boolean isSafeToReuseKVState()

Whether it's safe to reuse key-values from the state-backend, e.g for the purpose of optimization.

NOTE: this method should not be used to check for InternalPriorityQueue, as the priority queue could be stored on different locations, e.g RocksDB state-backend could store that on JVM heap if configuring HEAP as the time-service factory.

返回:

returns ture if safe to reuse the key-values from the state-backend.