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

Direct Known Subclasses:

CopyOnWriteStateTable, NestedMapsStateTable

public abstract class StateTable<K,N,S>
extends Object

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 RegisteredKeyedBackendStateMetaInfo<N,S>	metaInfo Combined meta information such as name and serializers for this state

Constructor Summary

Constructors

Constructor and Description
StateTable(InternalKeyContext<K> keyContext, RegisteredKeyedBackendStateMetaInfo<N,S> metaInfo)

Method Summary

Modifier and Type	Method and Description
abstract boolean	containsKey(N namespace) Returns whether this table contains a mapping for the composite of active key and given namespace.
abstract S	get(K key, N namespace) Returns the state for the composite of active key and given namespace.
abstract S	get(N namespace) Returns the state of the mapping for the composite of active key and given namespace.
abstract java.util.stream.Stream<K>	getKeys(N namespace)
RegisteredKeyedBackendStateMetaInfo<N,S>	getMetaInfo()
TypeSerializer<N>	getNamespaceSerializer()
TypeSerializer<S>	getStateSerializer()
boolean	isEmpty() Returns whether this NestedMapsStateTable is empty.
abstract void	put(K key, int keyGroup, N namespace, S state)
abstract void	put(N namespace, S state) Maps the composite of active key and given namespace to the specified state.
abstract S	putAndGetOld(N namespace, S state) Maps the composite of active key and given namespace to the specified state.
abstract void	remove(N namespace) Removes the mapping for the composite of active key and given namespace.
abstract 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(RegisteredKeyedBackendStateMetaInfo<N,S> metaInfo)
abstract int	size() Returns the total number of entries in this NestedMapsStateTable.
abstract int	sizeOfNamespace(Object namespace)
abstract <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

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 RegisteredKeyedBackendStateMetaInfo<N,S> metaInfo

Combined meta information such as name and serializers for this state

Constructor Detail

StateTable

public StateTable(InternalKeyContext<K> keyContext,
                  RegisteredKeyedBackendStateMetaInfo<N,S> metaInfo)

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.

Method Detail

isEmpty

public boolean isEmpty()

Returns whether this NestedMapsStateTable is empty.

Returns:

true if this NestedMapsStateTable has no elements, false otherwise.

See Also:

size()

size

public abstract int size()

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

Returns:

the number of entries in this NestedMapsStateTable.

get

public abstract 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 abstract 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 abstract void put(N namespace,
                         S state)

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.

Parameters:

namespace - the namespace. Not null.

state - the state. Can be null.

putAndGetOld

public abstract S putAndGetOld(N namespace,
                               S state)

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

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

getStateSerializer

public TypeSerializer<S> getStateSerializer()

getNamespaceSerializer

public TypeSerializer<N> getNamespaceSerializer()

getMetaInfo

public RegisteredKeyedBackendStateMetaInfo<N,S> getMetaInfo()

setMetaInfo

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

put

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

sizeOfNamespace

@VisibleForTesting
public abstract int sizeOfNamespace(Object namespace)