org.apache.kafka.streams.state

Interface SessionStore<K,AGG>

Type Parameters:

K - type of the record keys

AGG - type of the aggregated values

All Superinterfaces:

ReadOnlySessionStore<K,AGG>, StateStore

public interface SessionStore<K,AGG>
extends StateStore, ReadOnlySessionStore<K,AGG>

Interface for storing the aggregated values of sessions.

The key is internally represented as Windowed<K> that comprises the plain key and the Window that represents window start- and end-timestamp.

If two sessions are merged, a new session with new start- and end-timestamp must be inserted into the store while the two old sessions must be deleted.

Method Summary

Modifier and Type	Method and Description
void	put(Windowed<K> sessionKey, AGG aggregate) Write the aggregated value for the provided key to the store
void	remove(Windowed<K> sessionKey) Remove the session aggregated with provided Windowed key from the store

Methods inherited from interface org.apache.kafka.streams.processor.StateStore

close, flush, init, init, isOpen, name, persistent

Methods inherited from interface org.apache.kafka.streams.state.ReadOnlySessionStore

backwardFetch, backwardFetch, backwardFindSessions, backwardFindSessions, fetch, fetch, fetchSession, findSessions, findSessions

Method Detail

remove

void remove(Windowed<K> sessionKey)

Remove the session aggregated with provided Windowed key from the store

Parameters:

sessionKey - key of the session to remove

Throws:

NullPointerException - If null is used for sessionKey.

put

void put(Windowed<K> sessionKey,
         AGG aggregate)

Write the aggregated value for the provided key to the store

Parameters:

sessionKey - key of the session to write

aggregate - the aggregated value for the session, it can be null; if the serialized bytes are also null it is interpreted as deletes

Throws:

NullPointerException - If null is used for sessionKey.