PROCEDURE SUBSCRIBE(
  queueName      IN VARCHAR2,
  rule           IN VARCHAR2,
  subscriberName OUT NOCOPY VARCHAR2,
  errorNumber    OUT NUMBER
) AS
  aqAgent SYS.AQ$_AGENT;
  BEGIN
    SELECT 'S' || TO_CHAR(SYSTIMESTAMP, 'YYYYMMDDHH24MISSFF6') INTO subscriberName FROM DUAL;
    aqAgent := SYS.AQ$_AGENT(subscriberName, NULL, NULL);

    DBMS_AQADM.ADD_SUBSCRIBER(
      QUEUE_NAME => queueName,
      SUBSCRIBER => aqAgent,
      RULE       => rule
     );

    EXCEPTION WHEN OTHERS THEN 
      errorNumber := SQLCODE;
      RAISE;
END SUBSCRIBE;

PROCEDURE UNSUBSCRIBE(
  queueName      IN VARCHAR2,
  subscriberName IN VARCHAR2,
  errorNumber    OUT NUMBER
) AS
  aqAgent SYS.AQ$_AGENT;
  BEGIN
    aqAgent := SYS.AQ$_AGENT(subscriberName, NULL, NULL);
    DBMS_AQADM.REMOVE_SUBSCRIBER(queueName, aqAgent);

    EXCEPTION WHEN OTHERS THEN 
      errorNumber := SQLCODE;
      RAISE;
END UNSUBSCRIBE;