[TAP5-2207] It should be possible to be notified of session creations and invalidations

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 5.3, 5.4
• Component/s: tapestry-core
• Labels: event session
• Assignee: Unassigned
• Reporter: Jochen Kemnade
• Created: 22/Oct/13 11:19
• Updated: 22/Oct/13 11:19

Description

There are cases when it would be very helpful if one could subscribe to the creations and invalidations of sessions.

• Clear parts of a cache when a session is no longer valid
• Show how many users are currently using the application

Something like a `SessionStateHub` could be added, that is triggered when a `SessionImpl` is created or invalidated. Then, there should be methods to register listeners, e.g. `addSessionCreatedListener`, `addSessionWillBeInvalidatedListener`, `addSessionInvalidatedListener`.