org.apache.flink.runtime.state

Class AsynchronousKvStateSnapshot<K,N,S extends org.apache.flink.api.common.state.State,SD extends org.apache.flink.api.common.state.StateDescriptor<S,?>,Backend extends AbstractStateBackend>

java.lang.Object

org.apache.flink.runtime.state.AsynchronousKvStateSnapshot<K,N,S,SD,Backend>

Type Parameters:

K - The type of the key

N - The type of the namespace

S - The type of the State

SD - The type of the StateDescriptor

Backend - The type of the backend that can restore the state from this snapshot.

All Implemented Interfaces:

Closeable, Serializable, AutoCloseable, KvStateSnapshot<K,N,S,SD,Backend>, StateObject

public abstract class AsynchronousKvStateSnapshot<K,N,S extends org.apache.flink.api.common.state.State,SD extends org.apache.flink.api.common.state.StateDescriptor<S,?>,Backend extends AbstractStateBackend>
extends Object
implements KvStateSnapshot<K,N,S,SD,Backend>

KvStateSnapshot that asynchronously materializes the state that it represents. Instead of representing a materialized handle to state this would normally hold the (immutable) state internally and materializes it when materialize() is called.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
AsynchronousKvStateSnapshot()

Method Summary

Modifier and Type	Method and Description
void	close()
void	discardState() Discards the state referred to by this handle, to free up resources in the persistent storage.
long	getStateSize() Returns the size of the state in bytes.
abstract KvStateSnapshot<K,N,S,SD,Backend>	materialize() Materializes the state held by this AsynchronousKvStateSnapshot.
KvState<K,N,S,SD,Backend>	restoreState(Backend stateBackend, org.apache.flink.api.common.typeutils.TypeSerializer<K> keySerializer, ClassLoader classLoader) Loads the key/value state back from this snapshot.

Methods inherited from class java.lang.Object

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

Constructor Detail

AsynchronousKvStateSnapshot

public AsynchronousKvStateSnapshot()

Method Detail

materialize

public abstract KvStateSnapshot<K,N,S,SD,Backend> materialize()
                                                       throws Exception

Materializes the state held by this AsynchronousKvStateSnapshot.

Throws:

Exception

restoreState

public final KvState<K,N,S,SD,Backend> restoreState(Backend stateBackend,
                                                    org.apache.flink.api.common.typeutils.TypeSerializer<K> keySerializer,
                                                    ClassLoader classLoader)
                                             throws Exception

Description copied from interface: KvStateSnapshot

Loads the key/value state back from this snapshot.

Specified by:

restoreState in interface KvStateSnapshot<K,N,S extends org.apache.flink.api.common.state.State,SD extends org.apache.flink.api.common.state.StateDescriptor<S,?>,Backend extends AbstractStateBackend>

Parameters:

stateBackend - The state backend that created this snapshot and can restore the key/value state from this snapshot.

keySerializer - The serializer for the keys.

classLoader - The class loader for user-defined types.

Returns:

An instance of the key/value state loaded from this snapshot.

Throws:

Exception - Exceptions can occur during the state loading and are forwarded.

discardState

public void discardState()
                  throws Exception

Description copied from interface: StateObject

Discards the state referred to by this handle, to free up resources in the persistent storage. This method is called when the handle will not be used any more.

Specified by:

discardState in interface StateObject

Throws:

Exception

getStateSize

public long getStateSize()
                  throws Exception

Description copied from interface: StateObject

Returns the size of the state in bytes.

If the the size is not known, return 0.

Specified by:

getStateSize in interface StateObject

Returns:

Size of the state in bytes.

Throws:

Exception - If the operation fails during size retrieval.

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException