org.apache.flink.queryablestate.client.state

Class ImmutableValueState<V>

java.lang.Object

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

All Implemented Interfaces:

State, ValueState<V>

@PublicEvolving
public final class ImmutableValueState<V>
extends Object
implements ValueState<V>

A read-only ValueState 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 ValueStateDescriptor.

Field Summary

Fields

Modifier and Type	Field and Description
protected static UnsupportedOperationException	MODIFICATION_ATTEMPT_ERROR

Method Summary

Modifier and Type	Method and Description
void	clear() Removes the value mapped under the current key.
static <V> ImmutableValueState<V>	createState(ValueStateDescriptor<V> stateDescriptor, byte[] serializedState)
void	update(V newValue) Updates the operator state accessible by ValueState.value() to the given value.
V	value() 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

value

public V value()

Description copied from interface: ValueState

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.

If you didn't specify a default value when creating the ValueStateDescriptor this will return null when to value was previously set using ValueState.update(Object).

Specified by:

value in interface ValueState<V>

Returns:

The state value corresponding to the current input.

update

public void update(V newValue)

Description copied from interface: ValueState

Updates the operator state accessible by ValueState.value() to the given value. The next time ValueState.value() is called (for the same state partition) the returned state will represent the updated value. When a partitioned state is updated with null, the state for the current key will be removed and the default value is returned on the next access.

Specified by:

update in interface ValueState<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> ImmutableValueState<V> createState(ValueStateDescriptor<V> stateDescriptor,
                                                     byte[] serializedState)
                                              throws IOException

Throws:

IOException