Package org.apache.flink.runtime.state

Interface AsyncKeyedStateBackend<K>

All Superinterfaces:

AsyncExecutionController.SwitchContextListener<K>, AutoCloseable, CheckpointListener, Closeable, Disposable, InternalCheckpointListener, Snapshotable<SnapshotResult<KeyedStateHandle>>

All Known Implementing Classes:

AsyncKeyedStateBackendAdaptor, ForStKeyedStateBackend

@Internal
public interface AsyncKeyedStateBackend<K>
extends Snapshotable<SnapshotResult<KeyedStateHandle>>, InternalCheckpointListener, Disposable, Closeable, AsyncExecutionController.SwitchContextListener<K>

An async keyed state backend provides methods supporting to access keyed state asynchronously and in batch.

Method Summary

Modifier and Type	Method	Description
<N,S extends State,SV> S	createState(N defaultNamespace, TypeSerializer<N> namespaceSerializer, StateDescriptor<SV> stateDesc)	Creates and returns a new state.
StateExecutor	createStateExecutor()	Creates a StateExecutor which supports to execute a batch of state requests asynchronously.
void	dispose()	Disposes the object and releases all resources.
void	setup(StateRequestHandler stateRequestHandler)	Initializes with some contexts.
default void	switchContext(RecordContext<K> context)	By default, a state backend does nothing when a key is switched in async processing.

Methods inherited from interface org.apache.flink.api.common.state.CheckpointListener

notifyCheckpointAborted, notifyCheckpointComplete

Methods inherited from interface java.io.Closeable

close

Methods inherited from interface org.apache.flink.api.common.state.InternalCheckpointListener

notifyCheckpointSubsumed

Methods inherited from interface org.apache.flink.runtime.state.Snapshotable

snapshot

Method Detail

setup

void setup(@Nonnull
           StateRequestHandler stateRequestHandler)

Initializes with some contexts.

Parameters:

stateRequestHandler - which handles state request.

createState

@Nonnull
<N,S extends State,SV> S createState(@Nonnull
                                                 N defaultNamespace,
                                                 @Nonnull
                                                 TypeSerializer<N> namespaceSerializer,
                                                 @Nonnull
                                                 StateDescriptor<SV> stateDesc)
                                          throws Exception

Creates and returns a new state.

Type Parameters:

N - the type of namespace for partitioning.

S - The type of the public API state.

SV - The type of the stored state value.

Parameters:

defaultNamespace - the default namespace for this state.

namespaceSerializer - the serializer for namespace.

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception - Exceptions may occur during initialization of the state.

createStateExecutor

@Nonnull
StateExecutor createStateExecutor()

Creates a StateExecutor which supports to execute a batch of state requests asynchronously.

Notice that the AsyncKeyedStateBackend is responsible for shutting down the StateExecutors created by itself when they are no longer in use.

Returns:

a StateExecutor which supports to execute a batch of state requests asynchronously.

switchContext

default void switchContext(RecordContext<K> context)

By default, a state backend does nothing when a key is switched in async processing.

Specified by:

switchContext in interface AsyncExecutionController.SwitchContextListener<K>

dispose

void dispose()

Description copied from interface: Disposable

Disposes the object and releases all resources. After calling this method, calling any methods on the object may result in undefined behavior.

Specified by:

dispose in interface Disposable