Package org.apache.flink.queryablestate.client.state

Class ImmutableReducingState<V>

java.lang.Object

org.apache.flink.queryablestate.client.state.ImmutableReducingState<V>

All Implemented Interfaces:

AppendingState<V,V>, MergingState<V,V>, ReducingState<V>, State

public final class ImmutableReducingState<V>
extends Object
implements ReducingState<V>

A read-only ReducingState that does not allow for modifications.

This is the result returned when querying Flink's keyed state using the Queryable State Client and providing an ReducingStateDescriptor.

Field Summary

Fields

Modifier and Type	Field	Description
protected static UnsupportedOperationException	MODIFICATION_ATTEMPT_ERROR

Method Summary

Modifier and Type	Method	Description
void	add(V newValue)	Updates the operator state accessible by AppendingState.get() by adding the given value to the list of values.
void	clear()	Removes the value mapped under the current key.
static <V,S extends State> S	createState(StateDescriptor<S,V> stateDescriptor, byte[] serializedState)
V	get()	Returns the current value for the state.

Methods inherited from class java.lang.Object

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

Field Detail

MODIFICATION_ATTEMPT_ERROR

protected static final UnsupportedOperationException MODIFICATION_ATTEMPT_ERROR

Method Detail

get

public V get()

Description copied from interface: AppendingState

Returns the current value for the state. When the state is not partitioned the returned value is the same for all inputs in a given operator instance. If state partitioning is applied, the value returned depends on the current operator input, as the operator maintains an independent state for each partition.

NOTE TO IMPLEMENTERS: if the state is empty, then this method should return null.

Specified by:

get in interface AppendingState<V,V>

Returns:

The operator state value corresponding to the current input or null if the state is empty.

add

public void add(V newValue)

Description copied from interface: AppendingState

Updates the operator state accessible by AppendingState.get() by adding the given value to the list of values. The next time AppendingState.get() is called (for the same state partition) the returned state will represent the updated list.

If null is passed in, the behaviour is undefined (implementation related). TODO: An unified behaviour across all sub-classes.

Specified by:

add in interface AppendingState<V,V>

Parameters:

newValue - The new value for the state.

clear

public void clear()

Description copied from interface: State

Removes the value mapped under the current key.

Specified by:

clear in interface State

createState

public static <V,S extends State> S createState(StateDescriptor<S,V> stateDescriptor,
                                                      byte[] serializedState)
                                               throws IOException

Throws:

IOException