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

Method Summary

Modifier and Type	Method and Description
AGG	fetchSession(K key, long startTime, long endTime) Get the value of key from a single session.
KeyValueIterator<Windowed<K>,AGG>	findSessions(K keyFrom, K keyTo, long earliestSessionEndTime, long latestSessionStartTime) Fetch any sessions in the given range of keys and the sessions end is ≥ earliestSessionEndTime and the sessions start is ≤ latestSessionStartTime This iterator must be closed after use.
KeyValueIterator<Windowed<K>,AGG>	findSessions(K key, long earliestSessionEndTime, long latestSessionStartTime) Fetch any sessions with the matching key and the sessions end is ≥ earliestSessionEndTime and the sessions start is ≤ latestSessionStartTime This iterator must be closed after use.
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, isOpen, name, persistent

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

fetch, fetch

Method Detail

findSessions

KeyValueIterator<Windowed<K>,AGG> findSessions(K key,
                                               long earliestSessionEndTime,
                                               long latestSessionStartTime)

Fetch any sessions with the matching key and the sessions end is ≥ earliestSessionEndTime and the sessions start is ≤ latestSessionStartTime This iterator must be closed after use.

Parameters:

key - the key to return sessions for

earliestSessionEndTime - the end timestamp of the earliest session to search for

latestSessionStartTime - the end timestamp of the latest session to search for

Returns:

iterator of sessions with the matching key and aggregated values

Throws:

java.lang.NullPointerException - If null is used for key.

findSessions

KeyValueIterator<Windowed<K>,AGG> findSessions(K keyFrom,
                                               K keyTo,
                                               long earliestSessionEndTime,
                                               long latestSessionStartTime)

Fetch any sessions in the given range of keys and the sessions end is ≥ earliestSessionEndTime and the sessions start is ≤ latestSessionStartTime This iterator must be closed after use.

Parameters:

keyFrom - The first key that could be in the range

keyTo - The last key that could be in the range

earliestSessionEndTime - the end timestamp of the earliest session to search for

latestSessionStartTime - the end timestamp of the latest session to search for

Returns:

iterator of sessions with the matching keys and aggregated values

Throws:

java.lang.NullPointerException - If null is used for any key.

fetchSession

AGG fetchSession(K key,
                 long startTime,
                 long endTime)

Get the value of key from a single session.

Parameters:

key - the key to fetch

startTime - start timestamp of the session

endTime - end timestamp of the session

Returns:

The value or null if no session associated with the key can be found

Throws:

java.lang.NullPointerException - If null is used for any key.

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:

java.lang.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:

java.lang.NullPointerException - If null is used for sessionKey.