Get the current session.
public Session getSession ()
The processing engine creates a Session based on the unique MSISDN (or phone number) before starting the target application. The session will be persisted to database when the application reaches a state that wait for a trigger before continuing. For example, the "Send SMS" state sends SMS message out and wait for reply message before continuing. The processing engine will persist the session to the database prior to transition into the wait mode.
The session only lasts for a definite amount of time. By default, it is set to 450 secs. The session will be used by the "session expiration" daemon to terminate expired sessions.