private void cancelTimer() {
        Log.info("Offline message cleaning - Stop old timer if started");
        if (timer != null) {
            try {
                timer.cancel();
                timer.purge();
            } catch (Exception e) {
                Log.warn("Offline message cleaning - Could not stop the timer!", e);
            }
        }
        timer = null;
    }
Decide whether a message should be stored offline according to XEP-0160 and XEP-0334.

@param message The message to evaluate. Cannot be null.
@return <code>true</code> if the message should be stored offline, <code>false</code> otherwise.
xmppserver/src/main/java/org/jivesoftware/openfire/OfflineMessageStore.java