Rule language overview

This overview describes the key concepts of the Active Correlation Technology rule language.

A rule pattern is the representation of an event correlation situation (such as a threshold condition or duplicate event detection). The Active Correlation Technology rule language includes seven rule patterns that have been proven to represent most of the event correlation situations that IBM® customers need to address. Six of the seven rule patterns define stateful rules, and one of the patterns defines a stateless rule.

Stateful rules correlate multiple events that occur during a specific time period and generate a response to those events. Stateless rules process only a single event that meets a certain condition and generate a response to that event.
stateful rule
A rule that retains state information, which is information about the characteristics of a rule instance, for the purpose of acting on a collection of events over a period of time. Rules that are defined by any of the following rule patterns are stateful rules: collection, computation, duplicate, sequence, threshold, or timer.
stateless rule
A rule that does not retain state information and therefore can act only on one event at a time. A rule that is defined by the filter pattern is a stateless rule.