Package org.apache.kafka.streams.state

Interface ReadOnlySessionStore<K,AGG>

Type Parameters:

K - the key type

AGG - the aggregated value type

All Known Subinterfaces:

SessionStore<K,AGG>

All Known Implementing Classes:

CompositeReadOnlySessionStore, InMemorySessionStore, MeteredSessionStore, RocksDBSessionStore

public interface ReadOnlySessionStore<K,AGG>

A session store that only supports read operations. Implementations should be thread-safe as concurrent reads and writes are expected.

Method Summary

Modifier and Type	Method	Description
KeyValueIterator<Windowed<K>,AGG>	fetch(K key)	Retrieve all aggregated sessions for the provided key.
KeyValueIterator<Windowed<K>,AGG>	fetch(K from, K to)	Retrieve all aggregated sessions for the given range of keys.

Method Detail

fetch

KeyValueIterator<Windowed<K>,AGG> fetch(K key)

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.

Parameters:

key - record key to find aggregated session values for

Returns:

KeyValueIterator containing all sessions for the provided key.

Throws:

NullPointerException - If null is used for key.

fetch

KeyValueIterator<Windowed<K>,AGG> fetch(K from,
                                              K to)

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.

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.

Throws:

NullPointerException - If null is used for any of the keys.