The event catalog is a repository of event metadata.
The event catalog metadata consists of event definitions, which describe classes of events and their allowed content. (This is distinct from the event instance metadata you can access using the Eclipse Modeling Framework interfaces described in Accessing event instance metadata.) Applications can use the event catalog to manage their enterprise-specific event definitions, but must implement their own validation logic to ensure that events conform to these definitions.
Events defined according to the Common Base Event specification can be categorized into event classes based upon extension name (the value of the extensionName attribute). Using the event catalog, you can define the permitted content of a particular class of event by specifying what extended data elements events of that class can contain, as well as the permitted values for other Common Base Event properties. An event definition defines constraints on event content above and beyond those of the Common Base Event specification.
Event definitions are defined hierarchically and inherit the definitions of their parents. A single root event definition, event, defines the basic requirements of any event that conforms to the Common Base Event specification. All other event definitions inherit from this root definition. By default, this root event definition is automatically installed in the Event Catalog, along with event definitions for Event Catalog notification events (for more information, see Change notification).
By using the event catalog interfaces, you can create, delete, and query event definitions. (Once created, an event definition cannot be modified.) You can also list existing event definitions in a readable format, as well as importing and exporting event definitions in XML format.