Package org.apache.kafka.streams.state.internals

Class MeteredSessionStore<K,V>

java.lang.Object

org.apache.kafka.streams.state.internals.WrappedStateStore<SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>,Windowed<K>,V>

org.apache.kafka.streams.state.internals.MeteredSessionStore<K,V>

All Implemented Interfaces:

StateStore, CachedStateStore<Windowed<K>,V>, ReadOnlySessionStore<K,V>, SessionStore<K,V>

public class MeteredSessionStore<K,V>
extends WrappedStateStore<SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>,Windowed<K>,V>
implements SessionStore<K,V>

Method Summary

Modifier and Type	Method	Description
void	close()	Close the storage engine.
KeyValueIterator<Windowed<K>,V>	fetch(K key)	Retrieve all aggregated sessions for the provided key.
KeyValueIterator<Windowed<K>,V>	fetch(K from, K to)	Retrieve all aggregated sessions for the given range of keys.
V	fetchSession(K key, long startTime, long endTime)	Get the value of key from a single session.
KeyValueIterator<Windowed<K>,V>	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.
KeyValueIterator<Windowed<K>,V>	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.
void	flush()	Flush any cached data
void	init(ProcessorContext context, StateStore root)	Initializes this state store.
void	put(Windowed<K> sessionKey, V 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
boolean	setFlushListener(CacheFlushListener<Windowed<K>,V> listener, boolean sendOldValues)	Set the CacheFlushListener to be notified when entries are flushed from the cache to the underlying StateStore

Methods inherited from class org.apache.kafka.streams.state.internals.WrappedStateStore

isOpen, isTimestamped, name, persistent, wrapped

Methods inherited from class java.lang.Object

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

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

isOpen, name, persistent

Method Detail

init

public void init(ProcessorContext context,
                 StateStore root)

Description copied from interface: StateStore

Initializes this state store.

The implementation of this function must register the root store in the context via the ProcessorContext.register(StateStore, StateRestoreCallback) function, where the first StateStore parameter should always be the passed-in root object, and the second parameter should be an object of user's implementation of the StateRestoreCallback interface used for restoring the state store from the changelog.

Note that if the state store engine itself supports bulk writes, users can implement another interface BatchingStateRestoreCallback which extends StateRestoreCallback to let users implement bulk-load restoration logic instead of restoring one record at a time.

Specified by:

init in interface StateStore

Overrides:

init in class WrappedStateStore<SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>,Windowed<K>,V>

setFlushListener

public boolean setFlushListener(CacheFlushListener<Windowed<K>,V> listener,
                                boolean sendOldValues)

Description copied from interface: CachedStateStore

Set the CacheFlushListener to be notified when entries are flushed from the cache to the underlying StateStore

Specified by:

setFlushListener in interface CachedStateStore<K,V>

Overrides:

setFlushListener in class WrappedStateStore<SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>,Windowed<K>,V>

put

public void put(Windowed<K> sessionKey,
                V aggregate)

Description copied from interface: SessionStore

Write the aggregated value for the provided key to the store

Specified by:

put in interface SessionStore<K,V>

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

remove

public void remove(Windowed<K> sessionKey)

Description copied from interface: SessionStore

Remove the session aggregated with provided Windowed key from the store

Specified by:

remove in interface SessionStore<K,V>

Parameters:

sessionKey - key of the session to remove

fetchSession

public V fetchSession(K key,
                      long startTime,
                      long endTime)

Description copied from interface: SessionStore

Get the value of key from a single session.

Specified by:

fetchSession in interface SessionStore<K,V>

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

fetch

public KeyValueIterator<Windowed<K>,V> fetch(K key)

Description copied from interface: ReadOnlySessionStore

Retrieve all aggregated sessions for the provided key. This iterator must be closed after use. For each key, the iterator guarantees ordering of sessions, starting from the oldest/earliest available session to the newest/latest session.

Specified by:

fetch in interface ReadOnlySessionStore<K,V>

Parameters:

key - record key to find aggregated session values for

Returns:

KeyValueIterator containing all sessions for the provided key.

fetch

public KeyValueIterator<Windowed<K>,V> fetch(K from,
                                                   K to)

Description copied from interface: ReadOnlySessionStore

Retrieve all aggregated sessions for the given range of keys. This iterator must be closed after use. For each key, the iterator guarantees ordering of sessions, starting from the oldest/earliest available session to the newest/latest session.

Specified by:

fetch in interface ReadOnlySessionStore<K,V>

Parameters:

from - first key in the range to find aggregated session values for

to - last key in the range to find aggregated session values for

Returns:

KeyValueIterator containing all sessions for the provided key.

findSessions

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

Description copied from interface: SessionStore

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.

Specified by:

findSessions in interface SessionStore<K,V>

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

findSessions

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

Description copied from interface: SessionStore

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.

Specified by:

findSessions in interface SessionStore<K,V>

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

flush

public void flush()

Description copied from interface: StateStore

Flush any cached data

Specified by:

flush in interface StateStore

Overrides:

flush in class WrappedStateStore<SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>,Windowed<K>,V>

close

public void close()

Description copied from interface: StateStore

Close the storage engine. Note that this function needs to be idempotent since it may be called several times on the same state store.

Users only need to implement this function but should NEVER need to call this api explicitly as it will be called by the library automatically when necessary

Specified by:

close in interface StateStore

Overrides:

close in class WrappedStateStore<SessionStore<org.apache.kafka.common.utils.Bytes,byte[]>,Windowed<K>,V>