This change introduces SimpUserRegistry exposing an API to access
information about connected users, their sessions, and subscriptions
with STOMP/WebSocket messaging. Provides are methods to access users
as well as a method to find subscriptions given a Matcher strategy.
The DefaultSimpUserRegistry implementation is also a
SmartApplicationListener which listesn for ApplicationContext events
when users connect, disconnect, subscribe, and unsubscribe to
destinations.
The MultiServerUserRegistry implementation is a composite that
aggregates user information from the local SimpUserRegistry as well
as snapshots of user on remote application servers.
UserRegistryMessageHandler is used with MultiServerUserRegistry. It
broadcats user registry information through the broker and listens
for similar broadcasts from other servers. This must be enabled
explicitly when configuring the STOMP broker relay.
The existing UserSessionRegistry which was primiarly used internally
to resolve a user name to session id's has been deprecated and is no
longer used. If an application configures a custom UserSessionRegistr
still, it will be adapted accordingly to SimpUserRegistry but the
effect is rather limited (comparable to pre-existing functionality)
and will not work in multi-server scenarios.
Issue: SPR-12029
281588d7bb