The main focus of CEP is to correlate small units of time-based data within an ever-changing, ever-growing data cloud in order to detect hard-to-find special situations and to do something for these cases. In order to fully understand how it works, we first need to define a few other concepts. Let's start by defining events.
In order to understand events, let's first talk about a familiar concept. So far, we've dealt with facts that we insert into a Kie Session and how they can match a specific rule. Facts are very similar to events, except events have one extra feature: time of occurrence. Events are simply the data about any domain (represented as a Java object), along with the information about the time in which this information was true.
Pretty much anything that we record taking place at a specific time can be an event, as follows:
A sale in our eShop has a time for the transaction
A phone call has a starting time and...