How event patterns work

Event patterns respond to a visitor's interactive session with the runtime environment by updating their states and statuses and passing them to the runtime environment for processing.

When an interactive session starts, Interact tries to load any previous event pattern states that are associated with the current visitor's audience ID, if event pattern states exist.

When an event is posted, Interact updates the states and statuses of any event patterns that use the event.

If an event pattern is used during the session, such as during execution of an interactive flowchart, the status of the event pattern is retrieved.

When a session ends, the statuses of all the updated event patterns that are associated with the visitor's audience ID are stored in the database, if the audience ID is known (that is, the visitor's profile can be found in the profile data source). Otherwise, the event pattern states are discarded.

The advantage to this is that event pattern states are independent of user sessions, so that event activities from one user session are reflected in another session, while the audience ID matches and both sessions are active when those events occur.

The event pattern states for unknown users are discarded by default at the end of the session, unless the configuration property interact | services | eventPattern | persistUnknownUserStates is set to TRUE or the session parameter UACISavePatternStates is set to TRUE.

If the audience ID changes in the middle of a session, Interact tries to load the saved event pattern states for the new audience ID. In the scenario that the previous audience ID is unknown and the configuration setting (interact | services | eventPattern | mergeUnknowUserInSessionStates) is set to true, or the session parameter UACIMergePatternStates is set to true, the user event activities that belong to the previous audience ID in the same session are merged into the new audience ID.