WSO2 Governance Registry is based on WSO2 Carbon, which is a fully OSGi compliant component framework. To make the best out of the OSGi infrastructure, two main OSGi Services have been exposed for the exclusive use of dependent components.
The Registry Service:
This service exposes the Registry in two main perspectives, namely, "User Registry" and "System Registry." The user model of the Governance Registry treats both the system and a user in a similar manner. Therefore, a "System Registry" is made available for system-level operations such as start-up, shut-down and managing subscriptions to notifications. And, a "User Registry" is made available for user operations such as:
- Tagging resources
- Rating resources
- Creating resources
- Deleting resources
Both the embedded and remote registry instances implement this service and developers are provided with a uniform interface, despite the differences in the underlying implementation.
The Registry Eventing (and Notifications) Service:
This service exposes the WS-Eventing and Notification capabilities of the Governance Registry.
This service contains a number of WS-Eventing operations such as:
- Querying subscription status
- Obtaining an instance of the underlying subscription manager
It also contains Notification related functionality such as:
- Register (and query) event types
- Register (and query) exclusion patterns for a given event type
It is required to register an event type so that front-end users can subscribe to a particular event type.
If you want to allow restrict subscription to API level, you do not require registering the event type.
If you want to disallow subscription to a particular event type for a particular path or a set of paths, you can simply register one or more exclusion pattern for that event type.