EventHandler
Date: 2016-06-25

org.osgi.service.event

## Interface EventHandler

-     @ConsumerType
      public interface EventHandler

  Listener for Events.

  `EventHandler` objects are registered with the Framework service registry and are notified with an `Event` object when an event is sent or posted.

  `EventHandler` objects can inspect the received `Event` object to determine its topic and properties.

  `EventHandler` objects must be registered with a service property `EventConstants.EVENT_TOPIC` whose value is the list of topics in which the event handler is interested.

  For example:

       String[] topics = new String[] {"com/isv/*"};
       Hashtable ht = new Hashtable();
       ht.put(EventConstants.EVENT_TOPIC, topics);
       context.registerService(EventHandler.class.getName(), this, ht);

  Event Handler services can also be registered with an `EventConstants.EVENT_FILTER` service property to further filter the events. If the syntax of this filter is invalid, then the Event Handler must be ignored by the Event Admin service. The Event Admin service should log a warning.

  Security Considerations. Bundles wishing to monitor `Event` objects will require `ServicePermission[EventHandler,REGISTER]` to register an `EventHandler` service. The bundle must also have `TopicPermission[topic,SUBSCRIBE]` for the topic specified in the event in order to receive the event.

  See Also:
    `Event`

- - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `handleEvent(Event event)` Called by the `EventAdmin` service to notify the listener of an event.

- - ### Method Detail

    - #### handleEvent

          void handleEvent(Event event)

      Called by the `EventAdmin` service to notify the listener of an event.
      Parameters:
        `event` - The event that occurred.