The notification source and a set of parameters concerning the monitor MBean's state need to be specified when creating a new object of this class. The list of notifications fired by the monitor MBeans is the following:

• Common to all kind of monitors:
  • The observed object is not registered in the MBean server.
  • The observed attribute is not contained in the observed object.
  • The type of the observed attribute is not correct.
  • Any exception (except the cases described above) occurs when trying to get the value of the observed attribute.
• Common to the counter and the gauge monitors:
  • The threshold high or threshold low are not of the same type as the gauge (gauge monitors).
  • The threshold or the offset or the modulus are not of the same type as the counter (counter monitors).
• Counter monitors only:
  • The observed attribute has reached the threshold value.
• Gauge monitors only:
  • The observed attribute has exceeded the threshold high value.
  • The observed attribute has exceeded the threshold low value.
• String monitors only:
  • The observed attribute has matched the "string to compare" value.
  • The observed attribute has differed from the "string to compare" value.