Package org.apache.flink.table.runtime.sequencedmultisetstate

Interface SequencedMultiSetState<T>

Type Parameters:

T - The type of elements stored in the state.

All Known Implementing Classes:

LinkedMultiSetState

@Internal
public interface SequencedMultiSetState<T>

This class represents an interface for managing an ordered multi-set state in Apache Flink. It provides methods to add, append, and remove elements while maintaining insertion order.

The state supports two types of semantics for adding elements:

• Normal Set Semantics: Replaces an existing matching element with the new one.
• Multi-Set Semantics: Appends the new element, allowing duplicates.

Removal operations are supported with different result types, indicating the outcome of the removal process, such as whether all elements were removed, the last added element was removed, or no elements were removed.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	SequencedMultiSetState.StateChangeInfo<T>	Represents a result of a state changing operation.
static class	SequencedMultiSetState.StateChangeType	Removal Result Type.
static class	SequencedMultiSetState.Strategy

Method Summary

Modifier and Type	Method	Description
SequencedMultiSetState.StateChangeInfo<T>	add(T element, long timestamp)	Add the given element using the normal (non-multi) set semantics: if a matching element exists already, replace it (the timestamp is updated).
SequencedMultiSetState.StateChangeInfo<T>	append(T element, long timestamp)	Add the given element using the multi-set semantics, i.e. append.
void	clear()	Clear the state (in the current key context).
void	clearCache()	Clear caches.
static SequencedMultiSetState<org.apache.flink.table.data.RowData>	create(SequencedMultiSetStateContext parameters, org.apache.flink.api.common.functions.RuntimeContext ctx, String backendTypeIdentifier)
boolean	isEmpty()	Tells whether any state exists (in the given key context).
Iterator<org.apache.flink.api.java.tuple.Tuple2<T,Long>>	iterator()	Get iterator over all remaining elements and their timestamps, in order of insertion.
void	loadCache()	Load cache.
SequencedMultiSetState.StateChangeInfo<T>	remove(T element)	Remove the given element.

Method Detail

add

SequencedMultiSetState.StateChangeInfo<T> add(T element,
                                              long timestamp)
                                       throws Exception

Add the given element using the normal (non-multi) set semantics: if a matching element exists already, replace it (the timestamp is updated).

Throws:

Exception

append

SequencedMultiSetState.StateChangeInfo<T> append(T element,
                                                 long timestamp)
                                          throws Exception

Add the given element using the multi-set semantics, i.e. append.

Throws:

Exception

remove

SequencedMultiSetState.StateChangeInfo<T> remove(T element)
                                          throws Exception

Remove the given element. If there are multiple instances of the same element, remove the first one in insertion order.

Throws:

Exception

iterator

Iterator<org.apache.flink.api.java.tuple.Tuple2<T,Long>> iterator()
                                                                 throws Exception

Get iterator over all remaining elements and their timestamps, in order of insertion.

Throws:

Exception

isEmpty

boolean isEmpty()
         throws IOException

Tells whether any state exists (in the given key context).

Throws:

IOException

clear

void clear()

Clear the state (in the current key context).

loadCache

void loadCache()
        throws IOException

Load cache.

Throws:

IOException

clearCache

void clearCache()

Clear caches.

create

static SequencedMultiSetState<org.apache.flink.table.data.RowData> create(SequencedMultiSetStateContext parameters,
                                                                          org.apache.flink.api.common.functions.RuntimeContext ctx,
                                                                          String backendTypeIdentifier)