org.apache.flink.runtime.state.heap

Class StateTable<K,N,S>

java.lang.Object

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

Type Parameters:

K - type of key

N - type of namespace

S - type of state

All Implemented Interfaces:

Iterable<StateEntry<K,N,S>>, StateSnapshotRestore

Direct Known Subclasses:

CopyOnWriteStateTable, NestedMapsStateTable

public abstract class StateTable<K,N,S>
extends Object
implements StateSnapshotRestore, Iterable<StateEntry<K,N,S>>

Base class for state tables. Accesses to state are typically scoped by the currently active key, as provided through the InternalKeyContext.

Field Summary

Fields

Modifier and Type	Field and Description
protected InternalKeyContext<K>	keyContext The key context view on the backend.
protected StateMap<K,N,S>[]	keyGroupedStateMaps Map for holding the actual state objects.
protected KeyGroupRange	keyGroupRange The current key group range.
protected TypeSerializer<K>	keySerializer The serializer of the key.
protected RegisteredKeyValueStateBackendMetaInfo<N,S>	metaInfo Combined meta information such as name and serializers for this state.

Constructor Summary

Constructors

Constructor and Description
StateTable(InternalKeyContext<K> keyContext, RegisteredKeyValueStateBackendMetaInfo<N,S> metaInfo, TypeSerializer<K> keySerializer)

Method Summary

Modifier and Type	Method and Description
boolean	containsKey(N namespace) Returns whether this table contains a mapping for the composite of active key and given namespace.
protected abstract StateMap<K,N,S>	createStateMap()
S	get(K key, N namespace) Returns the state for the composite of active key and given namespace.
S	get(N namespace) Returns the state of the mapping for the composite of active key and given namespace.
int	getKeyGroupOffset()
java.util.stream.Stream<K>	getKeys(N namespace)
java.util.stream.Stream<Tuple2<K,N>>	getKeysAndNamespaces()
TypeSerializer<K>	getKeySerializer()
StateMap<K,N,S>	getMapForKeyGroup(int keyGroupIndex)
RegisteredKeyValueStateBackendMetaInfo<N,S>	getMetaInfo()
TypeSerializer<N>	getNamespaceSerializer()
StateMap<K,N,S>[]	getState() Returns the internal data structure.
InternalKvState.StateIncrementalVisitor<K,N,S>	getStateIncrementalVisitor(int recommendedMaxNumberOfReturnedRecords)
TypeSerializer<S>	getStateSerializer()
boolean	isEmpty() Returns whether this StateTable is empty.
Iterator<StateEntry<K,N,S>>	iterator()
StateSnapshotKeyGroupReader	keyGroupReader(int readVersion) This method returns a StateSnapshotKeyGroupReader that can be used to restore the state on a per-key-group basis.
void	put(K key, int keyGroup, N namespace, S state)
void	put(N namespace, S state) Maps the composite of active key and given namespace to the specified state.
void	remove(N namespace) Removes the mapping for the composite of active key and given namespace.
S	removeAndGetOld(N namespace) Removes the mapping for the composite of active key and given namespace, returning the state that was found under the entry.
void	setMetaInfo(RegisteredKeyValueStateBackendMetaInfo<N,S> metaInfo)
int	size() Returns the total number of entries in this StateTable.
int	sizeOfNamespace(Object namespace)
abstract IterableStateSnapshot<K,N,S>	stateSnapshot() Returns a snapshot of the state.
<T> void	transform(N namespace, T value, StateTransformationFunction<S,T> transformation) Applies the given StateTransformationFunction to the state (1st input argument), using the given value as second input argument.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

keyContext

protected final InternalKeyContext<K> keyContext

The key context view on the backend. This provides information, such as the currently active key.

metaInfo

protected RegisteredKeyValueStateBackendMetaInfo<N,S> metaInfo

Combined meta information such as name and serializers for this state.

keySerializer

protected final TypeSerializer<K> keySerializer

The serializer of the key.

keyGroupRange

protected final KeyGroupRange keyGroupRange

The current key group range.

keyGroupedStateMaps

protected final StateMap<K,N,S>[] keyGroupedStateMaps

Map for holding the actual state objects. The outer array represents the key-groups. All array positions will be initialized with an empty state map.

Constructor Detail

StateTable

public StateTable(InternalKeyContext<K> keyContext,
                  RegisteredKeyValueStateBackendMetaInfo<N,S> metaInfo,
                  TypeSerializer<K> keySerializer)

Parameters:

keyContext - the key context provides the key scope for all put/get/delete operations.

metaInfo - the meta information, including the type serializer for state copy-on-write.

keySerializer - the serializer of the key.

Method Detail

createStateMap

protected abstract StateMap<K,N,S> createStateMap()

stateSnapshot

@Nonnull
public abstract IterableStateSnapshot<K,N,S> stateSnapshot()

Description copied from interface: StateSnapshotRestore

Returns a snapshot of the state.

Specified by:

stateSnapshot in interface StateSnapshotRestore

isEmpty

public boolean isEmpty()

Returns whether this StateTable is empty.

Returns:

true if this StateTable has no elements, false otherwise.

See Also:

size()

size

public int size()

Returns the total number of entries in this StateTable. This is the sum of both sub-tables.

Returns:

the number of entries in this StateTable.

get

public S get(N namespace)

Returns the state of the mapping for the composite of active key and given namespace.

Parameters:

namespace - the namespace. Not null.

Returns:

the states of the mapping with the specified key/namespace composite key, or null if no mapping for the specified key is found.

containsKey

public boolean containsKey(N namespace)

Returns whether this table contains a mapping for the composite of active key and given namespace.

Parameters:

namespace - the namespace in the composite key to search for. Not null.

Returns:

true if this map contains the specified key/namespace composite key, false otherwise.

put

public void put(N namespace,
                S state)

Maps the composite of active key and given namespace to the specified state.

Parameters:

namespace - the namespace. Not null.

state - the state. Can be null.

remove

public void remove(N namespace)

Removes the mapping for the composite of active key and given namespace. This method should be preferred over #removeAndGetOld(N) when the caller is not interested in the old state.

Parameters:

namespace - the namespace of the mapping to remove. Not null.

removeAndGetOld

public S removeAndGetOld(N namespace)

Removes the mapping for the composite of active key and given namespace, returning the state that was found under the entry.

Parameters:

namespace - the namespace of the mapping to remove. Not null.

Returns:

the state of the removed mapping or null if no mapping for the specified key was found.

transform

public <T> void transform(N namespace,
                          T value,
                          StateTransformationFunction<S,T> transformation)
                   throws Exception

Applies the given StateTransformationFunction to the state (1st input argument), using the given value as second input argument. The result of StateTransformationFunction.apply(Object, Object) is then stored as the new state. This function is basically an optimization for get-update-put pattern.

Parameters:

namespace - the namespace. Not null.

value - the value to use in transforming the state. Can be null.

transformation - the transformation function.

Throws:

Exception - if some exception happens in the transformation function.

get

public S get(K key,
             N namespace)

Returns the state for the composite of active key and given namespace. This is typically used by queryable state.

Parameters:

key - the key. Not null.

namespace - the namespace. Not null.

Returns:

the state of the mapping with the specified key/namespace composite key, or null if no mapping for the specified key is found.

getKeys

public java.util.stream.Stream<K> getKeys(N namespace)

getKeysAndNamespaces

public java.util.stream.Stream<Tuple2<K,N>> getKeysAndNamespaces()

getStateIncrementalVisitor

public InternalKvState.StateIncrementalVisitor<K,N,S> getStateIncrementalVisitor(int recommendedMaxNumberOfReturnedRecords)

getState

@VisibleForTesting
public StateMap<K,N,S>[] getState()

Returns the internal data structure.

getKeyGroupOffset

public int getKeyGroupOffset()

getMapForKeyGroup

@VisibleForTesting
public StateMap<K,N,S> getMapForKeyGroup(int keyGroupIndex)

getKeySerializer

public TypeSerializer<K> getKeySerializer()

getStateSerializer

public TypeSerializer<S> getStateSerializer()

getNamespaceSerializer

public TypeSerializer<N> getNamespaceSerializer()

getMetaInfo

public RegisteredKeyValueStateBackendMetaInfo<N,S> getMetaInfo()

setMetaInfo

public void setMetaInfo(RegisteredKeyValueStateBackendMetaInfo<N,S> metaInfo)

put

public void put(K key,
                int keyGroup,
                N namespace,
                S state)

iterator

public Iterator<StateEntry<K,N,S>> iterator()

Specified by:

iterator in interface Iterable<StateEntry<K,N,S>>

sizeOfNamespace

@VisibleForTesting
public int sizeOfNamespace(Object namespace)

keyGroupReader

@Nonnull
public StateSnapshotKeyGroupReader keyGroupReader(int readVersion)

Description copied from interface: StateSnapshotRestore

This method returns a StateSnapshotKeyGroupReader that can be used to restore the state on a per-key-group basis. This method tries to return a reader for the given version hint.

Specified by:

keyGroupReader in interface StateSnapshotRestore

Parameters:

readVersion - the required version of the state to read.

Returns:

a reader that reads state by key-groups, for the given read version.