org.apache.flink.runtime.state.heap

Class StateMap<K,N,S>

java.lang.Object

org.apache.flink.runtime.state.heap.StateMap<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>>

Direct Known Subclasses:

CopyOnWriteSkipListStateMap, CopyOnWriteStateMap

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

Base class for state maps.

Constructor Summary

Constructors

Constructor and Description
StateMap()

Method Summary

Modifier and Type	Method and Description
abstract boolean	containsKey(K key, N namespace) Returns whether this map contains the specified key/namespace composite key.
abstract S	get(K key, N namespace) Returns the state for the composite of active key and given namespace.
abstract Stream<K>	getKeys(N namespace)
abstract InternalKvState.StateIncrementalVisitor<K,N,S>	getStateIncrementalVisitor(int recommendedMaxNumberOfReturnedRecords)
boolean	isEmpty() Returns whether this StateMap is empty.
abstract void	put(K key, N namespace, S state) Maps the specified key/namespace composite key to the specified value.
abstract S	putAndGetOld(K key, N namespace, S state) Maps the composite of active key and given namespace to the specified state.
void	releaseSnapshot(StateMapSnapshot<K,N,S,? extends StateMap<K,N,S>> snapshotToRelease) Releases a snapshot for this StateMap.
abstract void	remove(K key, N namespace) Removes the mapping for the composite of active key and given namespace.
abstract S	removeAndGetOld(K key, N namespace) Removes the mapping for the composite of active key and given namespace, returning the state that was found under the entry.
abstract int	size() Returns the total number of entries in this StateMap.
abstract int	sizeOfNamespace(Object namespace)
abstract StateMapSnapshot<K,N,S,? extends StateMap<K,N,S>>	stateSnapshot() Creates a snapshot of this StateMap, to be written in checkpointing.
abstract <T> void	transform(K key, 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, iterator, spliterator

Constructor Detail

StateMap

public StateMap()

Method Detail

isEmpty

public boolean isEmpty()

Returns whether this StateMap is empty.

Returns:

true if this StateMap has no elements, false otherwise.

See Also:

size()

size

public abstract int size()

Returns the total number of entries in this StateMap.

Returns:

the number of entries in this StateMap.

get

public abstract S get(K key,
                      N namespace)

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

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.

containsKey

public abstract boolean containsKey(K key,
                                    N namespace)

Returns whether this map contains the specified key/namespace composite key.

Parameters:

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

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(K key,
                         N namespace,
                         S state)

Maps the specified key/namespace composite key to the specified value. This method should be preferred over #putAndGetOld(K, N, S) (key, Namespace, State) when the caller is not interested in the old state.

Parameters:

key - the key. Not null.

namespace - the namespace. Not null.

state - the state. Can be null.

putAndGetOld

public abstract S putAndGetOld(K key,
                               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:

key - the key. Not null.

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(K key,
                            N namespace)

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

Parameters:

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

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

removeAndGetOld

public abstract S removeAndGetOld(K key,
                                  N namespace)

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

Parameters:

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

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(K key,
                                   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:

key - the key. Not null.

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.

getKeys

public abstract Stream<K> getKeys(N namespace)

getStateIncrementalVisitor

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

stateSnapshot

@Nonnull
public abstract StateMapSnapshot<K,N,S,? extends StateMap<K,N,S>> stateSnapshot()

Creates a snapshot of this StateMap, to be written in checkpointing. Users should call releaseSnapshot(StateMapSnapshot) after using the returned object.

Returns:

a snapshot from this StateMap, for checkpointing.

releaseSnapshot

public void releaseSnapshot(StateMapSnapshot<K,N,S,? extends StateMap<K,N,S>> snapshotToRelease)

Releases a snapshot for this StateMap. This method should be called once a snapshot is no more needed.

Parameters:

snapshotToRelease - the snapshot to release, which was previously created by this state map.

sizeOfNamespace

@VisibleForTesting
public abstract int sizeOfNamespace(Object namespace)