public void addSessionListener(SessionListener listener,boolean force) throws SessionException {
  if (!force && sessionState != SessionState.VALID) {
    throw new SessionException(SessionBundle.rbName,"invalidSessionState",null);
  }
  localSessionEventListeners.add(listener);
}

public void addSessionListener ( SessionListener listener , boolean force ) throws SessionException { if ( ! force && sessionState != SessionState . VALID ) { throw new SessionException ( SessionBundle . rbName , "invalidSessionState" , null ) ; } localSessionEventListeners . add ( listener ) ; }
adds a session listener for session change events .
