org.apache.flink.runtime.state.heap

Class NestedMapsStateTable<K,N,S>

java.lang.Object

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

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

Type Parameters:

K - type of key.

N - type of namespace.

S - type of state.

All Implemented Interfaces:

StateSnapshotRestore

@Internal
public class NestedMapsStateTable<K,N,S>
extends StateTable<K,N,S>

This implementation of StateTable uses nested HashMap objects. It is also maintaining a partitioning by key-group.

In contrast to CopyOnWriteStateTable, this implementation does not support asynchronous snapshots. However, it might have a better memory footprint for some use-cases, e.g. it is naturally de-duplicating namespace objects.

Field Summary

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

keyContext, metaInfo

Constructor Summary

Constructors

Constructor and Description
NestedMapsStateTable(InternalKeyContext<K> keyContext, RegisteredKeyValueStateBackendMetaInfo<N,S> metaInfo) Creates a new NestedMapsStateTable for the given key context and meta info.

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.
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.
java.util.stream.Stream<K>	getKeys(N namespace)
Map<N,Map<K,S>>[]	getState() Returns the internal data structure.
void	put(K key, int keyGroupIndex, N namespace, S value)
void	put(N namespace, S state) Maps the composite of active key and given namespace to the specified state.
S	putAndGetOld(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.
int	size() Returns the total number of entries in this StateTable.
int	sizeOfNamespace(Object namespace)
org.apache.flink.runtime.state.heap.NestedMapsStateTable.NestedMapsStateTableSnapshot<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 org.apache.flink.runtime.state.heap.StateTable

getMetaInfo, getNamespaceSerializer, getStateSerializer, isEmpty, keyGroupReader, setMetaInfo

Methods inherited from class java.lang.Object

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

Constructor Detail

NestedMapsStateTable

public NestedMapsStateTable(InternalKeyContext<K> keyContext,
                            RegisteredKeyValueStateBackendMetaInfo<N,S> metaInfo)

Creates a new NestedMapsStateTable for the given key context and meta info.

Parameters:

keyContext - the key context.

metaInfo - the meta information for this state table.

Method Detail

getState

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

Returns the internal data structure.

size

public int size()

Description copied from class: StateTable

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

Specified by:

size in class StateTable<K,N,S>

Returns:

the number of entries in this StateTable.

get

public S get(N namespace)

Description copied from class: StateTable

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

Specified by:

get in class StateTable<K,N,S>

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)

Description copied from class: StateTable

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

Specified by:

containsKey in class StateTable<K,N,S>

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)

Description copied from class: StateTable

Maps the composite of active key and given namespace to the specified state. This method should be preferred over #putAndGetOld(N, S) (Namespace, State)} when the caller is not interested in the old state.

Specified by:

put in class StateTable<K,N,S>

Parameters:

namespace - the namespace. Not null.

state - the state. Can be null.

putAndGetOld

public S putAndGetOld(N namespace,
                      S state)

Description copied from class: StateTable

Maps the composite of active key and given namespace to the specified state. Returns the previous state that was registered under the composite key.

Specified by:

putAndGetOld in class StateTable<K,N,S>

Parameters:

namespace - the namespace. Not null.

state - the state. Can be null.

Returns:

the state of any previous mapping with the specified key or null if there was no such mapping.

remove

public void remove(N namespace)

Description copied from class: StateTable

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.

Specified by:

remove in class StateTable<K,N,S>

Parameters:

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

removeAndGetOld

public S removeAndGetOld(N namespace)

Description copied from class: StateTable

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

Specified by:

removeAndGetOld in class StateTable<K,N,S>

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.

get

public S get(K key,
             N namespace)

Description copied from class: StateTable

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

Specified by:

get in class StateTable<K,N,S>

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)

Specified by:

getKeys in class StateTable<K,N,S>

put

public void put(K key,
                int keyGroupIndex,
                N namespace,
                S value)

Specified by:

put in class StateTable<K,N,S>

sizeOfNamespace

public int sizeOfNamespace(Object namespace)

Specified by:

sizeOfNamespace in class StateTable<K,N,S>

transform

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

Description copied from class: StateTable

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.

Specified by:

transform in class StateTable<K,N,S>

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.

stateSnapshot

@Nonnull
public org.apache.flink.runtime.state.heap.NestedMapsStateTable.NestedMapsStateTableSnapshot<K,N,S> stateSnapshot()

Description copied from interface: StateSnapshotRestore

Returns a snapshot of the state.