Information Technology Reference
In-Depth Information
CEP
Now that we understand the concept of complex events, we need a way to actually correl-
ate events, infer those events, and take specific actions from all the different correlations
between events. Event processing is based on providing analysis and tracking tools of dif-
ferent events from different sources.
CEP extends that definition to add the possibility of combining said events into complex
events by utilizing analysis tools, and later on using these events to feed more complex
situations. Drools provides such a mechanism through business rules writing and execu-
tion. Rules provide a very quick and performing way to infer events and act accordingly,
which is why it has been widely used by many real-time applications that need to have the
fastest reaction possible.
CEP is all about analyzing events and reacting as soon as a situation of interest is found.
Events might be coming from different sources, with different structures, and at different
moments in time. It is the responsibility of the CEP agent to both define a structure of pro-
cessing behind the specific data (in case of Drools, that structure is defined using rules) as
well as a way to introduce information to the runtime (in case of Drools, through event in-
sertion in the rule memory).
CEP agents are one piece of a system that will need to produce events, and usually the out-
puts of the rules will be fed to some other component that is prepared to consume said out-
puts. These components have been abstracted and defined within an
Event-driven archi-
tecture
(
EDA
).
