Apama inverts the paradigm of traditional data-centric systems. Rather than the store > index > search model of those architectures, Apama introduces the correlator — a real-time, event processing engine. An Apama application comprises monitors that specify the events or patterns of events that interest you. These specifications are the logical equivalent of database queries. After you load monitors into the correlator, incoming events flow over them and they monitor these event streams for the events and patterns you specified. When a matching event or pattern is found the correlator processes it according to the rules you specify.

Apama's architecture is further distinguished by its ability to support huge numbers of monitors operating simultaneously. Each can have its own logic for monitoring the event streams, seeking out patterns and, upon detection, triggering specified actions.

EPL, Apama's native event programming language, lets developers define rules for processing complex events. Such rules let the correlator find temporal and causal relationships among events.

Messages on a variety of transports carry events to and from correlators. Apama connectivity plug-ins translate application-specific data into Apama application event formats that the correlator can process.

Apama components can be connected to each other by executing the Apama engine_connect tool with specification of an explicit point-to-point connection.

The following figure illustrates the Apama architecture. Each component is described later in this section.