/** Terminates the subscription (subscription goes into 'terminated' state). */
 public void terminate(String reason) {
   Message req = MessageFactory.createNotifyRequest(this, event, id, null, null);
   SubscriptionStateHeader sh = new SubscriptionStateHeader(TERMINATED);
   if (reason != null) sh.setReason(reason);
   // sh.setExpires(0);
   req.setSubscriptionStateHeader(sh);
   notify(req);
 }
 /** Sends a NOTIFY. */
 public void notify(String state, int expires, String content_type, String body) {
   Message req = MessageFactory.createNotifyRequest(this, event, id, content_type, body);
   if (state != null) {
     SubscriptionStateHeader sh = new SubscriptionStateHeader(state);
     if (expires >= 0) sh.setExpires(expires);
     req.setSubscriptionStateHeader(sh);
   }
   notify(req);
 }