org.apache.flink.runtime.state.heap

Class CopyOnWriteStateMapSnapshot<K,N,S>

java.lang.Object

org.apache.flink.runtime.state.heap.StateMapSnapshot<K,N,S,CopyOnWriteStateMap<K,N,S>>

org.apache.flink.runtime.state.heap.CopyOnWriteStateMapSnapshot<K,N,S>

Type Parameters:

K - type of key

N - type of namespace

S - type of state

public class CopyOnWriteStateMapSnapshot<K,N,S>
extends StateMapSnapshot<K,N,S,CopyOnWriteStateMap<K,N,S>>

This class represents the snapshot of a CopyOnWriteStateMap.

IMPORTANT: Please notice that snapshot integrity of entries in this class rely on proper copy-on-write semantics through the CopyOnWriteStateMap that created the snapshot object, but all objects in this snapshot must be considered as READ-ONLY!. The reason is that the objects held by this class may or may not be deep copies of original objects that may still used in the CopyOnWriteStateMap. This depends for each entry on whether or not it was subject to copy-on-write operations by the CopyOnWriteStateMap. Phrased differently: the CopyOnWriteStateMap provides copy-on-write isolation for this snapshot, but this snapshot does not isolate modifications from the CopyOnWriteStateMap!

Field Summary

Fields inherited from class org.apache.flink.runtime.state.heap.StateMapSnapshot

owningStateMap

Method Summary

Modifier and Type	Method and Description
boolean	isReleased()
void	release() Release the snapshot.
void	writeState(TypeSerializer<K> keySerializer, TypeSerializer<N> namespaceSerializer, TypeSerializer<S> stateSerializer, DataOutputView dov, StateSnapshotTransformer<S> stateSnapshotTransformer) Writes the state in this snapshot to output.

Methods inherited from class org.apache.flink.runtime.state.heap.StateMapSnapshot

isOwner

Methods inherited from class java.lang.Object

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

Method Detail

release

public void release()

Description copied from class: StateMapSnapshot

Release the snapshot.

Overrides:

release in class StateMapSnapshot<K,N,S,CopyOnWriteStateMap<K,N,S>>

isReleased

public boolean isReleased()

writeState

public void writeState(TypeSerializer<K> keySerializer,
                       TypeSerializer<N> namespaceSerializer,
                       TypeSerializer<S> stateSerializer,
                       @Nonnull
                       DataOutputView dov,
                       @Nullable
                       StateSnapshotTransformer<S> stateSnapshotTransformer)
                throws IOException

Description copied from class: StateMapSnapshot

Writes the state in this snapshot to output. The state need to be transformed with the given transformer if the transformer is non-null.

Specified by:

writeState in class StateMapSnapshot<K,N,S,CopyOnWriteStateMap<K,N,S>>

Parameters:

keySerializer - the key serializer.

namespaceSerializer - the namespace serializer.

stateSerializer - the state serializer.

dov - the output.

stateSnapshotTransformer - state transformer, and can be null.

Throws:

IOException - on write-related problems.