@@ -15,14 +15,15 @@ Common events are classified into system common events and custom common events.
Common events are also classified into unordered, ordered, and sticky common events.
- Unordered common events: common events that CES forwards based on the subscription sequence, regardless of whether subscribers receive the events.
- Unordered common events: common events that CES forwards regardless of whether subscribers receive the events and when they subscribe to the events.
- Ordered common events: common events that CES forwards based on the subscriber priority. CES forwards common events to the subscriber with lower priority only after receiving a reply from the previous subscriber with higher priority.
- Ordered common events: common events that CES forwards based on the subscriber priority. CES forwards common events to the subscriber with lower priority only after receiving a reply from the previous subscriber with higher priority. Subscribers with the same priority receive common events in a random order.
- Sticky common events: common events that can be sent to a subscriber before they initiate a subscription. Only system applications and system services can send sticky common events, and they must request the **ohos.permission.COMMONEVENT_STICKY** permission. For details about the configuration, see [Permission Application Guide](../security/accesstoken-guidelines.md#declaring-permissions-in-the-configuration-file).
- Sticky common events: common events that can be sent to a subscriber before or after they initiate a subscription. Only system applications and system services can send sticky common events, which remain in the system after being sent. The sends must first request the **ohos.permission.COMMONEVENT_STICKY** permission. For details about the configuration, see [Permission Application Guide](../security/accesstoken-guidelines.md#declaring-permissions-in-the-configuration-file).
Each application can subscribe to common events as required. After your application subscribes to a common event, the system sends it to your application every time the event is published. Such an event may be published by the system, other applications, or your own application.
