org.apache.flink.runtime.state.internal

Interface InternalKvState<K,N,V>

Type Parameters:

K - The type of key the state is associated to

N - The type of the namespace

V - The type of values kept internally in state

All Superinterfaces:

State

All Known Subinterfaces:

InternalAggregatingState<K,N,IN,SV,OUT>, InternalAppendingState<K,N,IN,SV,OUT>, InternalListState<K,N,T>, InternalMapState<K,N,UK,UV>, InternalMergingState<K,N,IN,SV,OUT>, InternalReducingState<K,N,T>, InternalValueState<K,N,T>

All Known Implementing Classes:

AbstractHeapState, AbstractRocksDBState

public interface InternalKvState<K,N,V>
extends State

The InternalKvState is the root of the internal state type hierarchy, similar to the State being the root of the public API state hierarchy.

The internal state classes give access to the namespace getters and setters and access to additional functionality, like raw value access or state merging.

The public API state hierarchy is intended to be programmed against by Flink applications. The internal state hierarchy holds all the auxiliary methods that are used by the runtime and not intended to be used by user applications. These internal methods are considered of limited use to users and only confusing, and are usually not regarded as stable across releases.

Each specific type in the internal state hierarchy extends the type from the public state hierarchy:

             State
               |
               +-------------------InternalKvState
               |                         |
          MergingState                   |
               |                         |
               +-----------------InternalMergingState
               |                         |
      +--------+------+                  |
      |               |                  |
 ReducingState    ListState        +-----+-----------------+
      |               |            |                       |
      +-----------+   +-----------   -----------------InternalListState
                  |                |
                  +---------InternalReducingState
 

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	InternalKvState.StateIncrementalVisitor<K,N,V> The state entry visitor which supports remove and update of the last returned entries.

Method Summary

Modifier and Type	Method and Description
TypeSerializer<K>	getKeySerializer() Returns the TypeSerializer for the type of key this state is associated to.
TypeSerializer<N>	getNamespaceSerializer() Returns the TypeSerializer for the type of namespace this state is associated to.
byte[]	getSerializedValue(byte[] serializedKeyAndNamespace, TypeSerializer<K> safeKeySerializer, TypeSerializer<N> safeNamespaceSerializer, TypeSerializer<V> safeValueSerializer) Returns the serialized value for the given key and namespace.
InternalKvState.StateIncrementalVisitor<K,N,V>	getStateIncrementalVisitor(int recommendedMaxNumberOfReturnedRecords) Get global visitor of state entries.
TypeSerializer<V>	getValueSerializer() Returns the TypeSerializer for the type of value this state holds.
void	setCurrentNamespace(N namespace) Sets the current namespace, which will be used when using the state access methods.

Methods inherited from interface org.apache.flink.api.common.state.State

clear

Method Detail

getKeySerializer

TypeSerializer<K> getKeySerializer()

Returns the TypeSerializer for the type of key this state is associated to.

getNamespaceSerializer

TypeSerializer<N> getNamespaceSerializer()

Returns the TypeSerializer for the type of namespace this state is associated to.

getValueSerializer

TypeSerializer<V> getValueSerializer()

Returns the TypeSerializer for the type of value this state holds.

setCurrentNamespace

void setCurrentNamespace(N namespace)

Sets the current namespace, which will be used when using the state access methods.

Parameters:

namespace - The namespace.

getSerializedValue

byte[] getSerializedValue(byte[] serializedKeyAndNamespace,
                          TypeSerializer<K> safeKeySerializer,
                          TypeSerializer<N> safeNamespaceSerializer,
                          TypeSerializer<V> safeValueSerializer)
                   throws Exception

Returns the serialized value for the given key and namespace.

If no value is associated with key and namespace, null is returned.

TO IMPLEMENTERS: This method is called by multiple threads. Anything stateful (e.g. serializers) should be either duplicated or protected from undesired consequences of concurrent invocations.

Parameters:

serializedKeyAndNamespace - Serialized key and namespace

safeKeySerializer - A key serializer which is safe to be used even in multi-threaded context

safeNamespaceSerializer - A namespace serializer which is safe to be used even in multi-threaded context

safeValueSerializer - A value serializer which is safe to be used even in multi-threaded context

Returns:

Serialized value or null if no value is associated with the key and namespace.

Throws:

Exception - Exceptions during serialization are forwarded

getStateIncrementalVisitor

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

Get global visitor of state entries.

Parameters:

recommendedMaxNumberOfReturnedRecords - hint to the visitor not to exceed this number of returned records per nextEntries call, it can still be exceeded by some smaller constant.

Returns:

global iterator over state entries