Package org.springframework.ai.session

Class InMemorySessionRepository

java.lang.Object

org.springframework.ai.session.InMemorySessionRepository

All Implemented Interfaces:

SessionRepository

public final class InMemorySessionRepository
extends Object
implements SessionRepository

A thread-safe SessionRepository in memory, for tests and demos: the sessions are lost on restart and not shared across instances. A session and its log are kept together, and every mutation is one ConcurrentHashMap.compute(K, java.util.function.BiFunction<? super K, ? super V, ? extends V>).

Since:

2.1.0

Author:

Christian Tzolov

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	InMemorySessionRepository.Builder	Builds an InMemorySessionRepository.

Method Summary

Modifier and Type	Method	Description
void	appendEvent(SessionEvent event)	Appends one event to the log of the session named by SessionEvent.getSessionId().
boolean	appendEvents(String sessionId, List<SessionEvent> events, long expectedVersion)	Appends several events in order, atomically, only if the log's version equals expectedVersion; otherwise nothing is written and false is returned.
static InMemorySessionRepository.Builder	builder()	Returns a new InMemorySessionRepository.Builder.
void	delete(String sessionId)	Deletes the session and its events.
int	deleteExpiredSessions(Instant before)	Deletes every session that expired before the given instant, with their events, in one atomic step per session, so a session whose expiry was extended concurrently (SessionRepository.save(org.springframework.ai.session.Session)) is kept.
@Nullable Session	findById(String sessionId)
List<Session>	findByMetadata(String name, String value)	The sessions whose metadata holds value under name, oldest first (creation time, then id).
List<SessionEvent>	findEvents(String sessionId, EventFilter filter)	The events of the session the filter selects, oldest first; an empty list for a session that does not exist.
long	getEventVersion(String sessionId)	The version of the session's log, advanced on every SessionRepository.appendEvent(org.springframework.ai.session.SessionEvent) that appends a new event and on every successful SessionRepository.appendEvents(java.lang.String, java.util.List<org.springframework.ai.session.SessionEvent>, long); 0 for a session that does not exist or has no events.
Session	save(Session session)	Persists session metadata (create or update).
boolean	saveIfAbsent(Session session)	Inserts the session unless one with the same id exists, atomically: a primary-key-guarded INSERT, or a compare-and-set put.

Methods inherited from class java.lang.Object

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

Method Details

builder

public static InMemorySessionRepository.Builder builder()

Returns a new InMemorySessionRepository.Builder.

save

public Session save(Session session)

Description copied from interface: SessionRepository

Persists session metadata (create or update). If the session already exists its event log and its original Session.createdAt() are preserved; the other metadata fields are replaced.

Specified by:

save in interface SessionRepository

Returns:

the saved session

saveIfAbsent

public boolean saveIfAbsent(Session session)

Description copied from interface: SessionRepository

Inserts the session unless one with the same id exists, atomically: a primary-key-guarded INSERT, or a compare-and-set put. SessionService.create(org.springframework.ai.session.CreateSessionRequest) relies on it, so two concurrent creates of one id cannot both succeed.

Specified by:

saveIfAbsent in interface SessionRepository

Returns:

true if the session was inserted, false if one with the same id exists; the existing session is left untouched

findById

public @Nullable Session findById(String sessionId)

Specified by:

findById in interface SessionRepository

findByMetadata

public List<Session> findByMetadata(String name,
 String value)

Description copied from interface: SessionRepository

The sessions whose metadata holds value under name, oldest first (creation time, then id). The one scoped lookup of the store, in the shape of Spring Session's findByIndexNameAndIndexValue: the store indexes attributes and has no notion of ownership. Every store indexes SessionAttributes.PRINCIPAL_NAME; a store that cannot index every key documents which others it answers for.

Specified by:

findByMetadata in interface SessionRepository

Parameters:

name - the metadata key

value - the value, compared as a string

deleteExpiredSessions

public int deleteExpiredSessions(Instant before)

Description copied from interface: SessionRepository

Deletes every session that expired before the given instant, with their events, in one atomic step per session, so a session whose expiry was extended concurrently (SessionRepository.save(org.springframework.ai.session.Session)) is kept.

Specified by:

deleteExpiredSessions in interface SessionRepository

Parameters:

before - the expiry cut-off

Returns:

the number of sessions deleted

delete

public void delete(String sessionId)

Description copied from interface: SessionRepository

Deletes the session and its events.

Specified by:

delete in interface SessionRepository

appendEvent

public void appendEvent(SessionEvent event)

Description copied from interface: SessionRepository

Appends one event to the log of the session named by SessionEvent.getSessionId().

Idempotent by id: an event whose id is already in the session's log is a retried append and a no-op, neither a duplicate nor an error, and the version is not advanced. A caller that wants to retry safely supplies its own id rather than the builder's random one. Event ids are unique across sessions: a persistent store keys events by id alone and rejects an id used by another session rather than dropping the event.

Specified by:

appendEvent in interface SessionRepository

appendEvents

public boolean appendEvents(String sessionId,
 List<SessionEvent> events,
 long expectedVersion)

Description copied from interface: SessionRepository

Appends several events in order, atomically, only if the log's version equals expectedVersion; otherwise nothing is written and false is returned. On success the version advances once, whatever the number of events. This is how a compaction is recorded: one EventType.COMPACTION boundary and its summary events, with the version check keeping two concurrent compactions from both landing. Read SessionRepository.getEventVersion(java.lang.String) before SessionRepository.findEvents(java.lang.String, org.springframework.ai.session.EventFilter), then pass that version here.

Specified by:

appendEvents in interface SessionRepository

Parameters:

sessionId - the session whose log is appended to; every event must belong to it

events - the events, in order; at least one, with ids that are new to the log

expectedVersion - the version the caller read

Returns:

true when the events were appended, false when the version did not match

getEventVersion

public long getEventVersion(String sessionId)

Description copied from interface: SessionRepository

The version of the session's log, advanced on every SessionRepository.appendEvent(org.springframework.ai.session.SessionEvent) that appends a new event and on every successful SessionRepository.appendEvents(java.lang.String, java.util.List<org.springframework.ai.session.SessionEvent>, long); 0 for a session that does not exist or has no events. Read it before SessionRepository.findEvents(java.lang.String, org.springframework.ai.session.EventFilter), so that the version passed to SessionRepository.appendEvents(java.lang.String, java.util.List<org.springframework.ai.session.SessionEvent>, long) is not newer than the events read.

Specified by:

getEventVersion in interface SessionRepository

findEvents

public List<SessionEvent> findEvents(String sessionId,
 EventFilter filter)

Description copied from interface: SessionRepository

The events of the session the filter selects, oldest first; an empty list for a session that does not exist.

A EventFilter.Window.Last window returns the newest N matching events, extended back to the start of the turn it lands in (the nearest preceding turn start among the matches), so a tool call is never returned without its results; the extension is skipped when no turn start precedes the window. With EventFilter.activeView() the filter applies to the active view, the events the newest EventType.COMPACTION boundary names and everything appended after it, rather than to the whole log.

EventFilter.apply(List) is the reference implementation of both. A store pushes the criteria and the window down to its query, so that a read does not cost the whole log, and may fetch only the rows a view can contain and hand them to apply, as JdbcSessionRepository does.

Specified by:

findEvents in interface SessionRepository