Apama 10.3 | Apama Documentation | Developing Apama Applications | EPL Reference | Events and Event Listeners
Events and Event Listeners
Event definitions
Event templates
Event listener definitions
Event lifecycle
Event listener lifecycle
Event processing order for monitors
Event processing order for queries
Event expressions
Event channels
In EPL, an event is a data object that is a notification of something happening, such as arrival of a customer order, shipment delivery, sensor state change, stock trade, or myriad other things. Each kind of event has an event type name, zero or more data elements or fields, and zero or more event actions associated with it.
Event objects can also be used simply as complex data structures to hold multiple related data values. They can also be used as a container for actions that can be shared by multiple monitors.
Event objects are hierarchical structures that can contain simple values, other events, and arrays.
When the correlator executes an on statement, it creates an event listener. An event listener watches for an event, or a sequence of events, that matches the event or event sequence specified in the on statement. Conceptually, event listeners sift the events that come in to the correlator and watch for matching events.

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