Interface EventListener

  • All Known Subinterfaces:
    TypedEventListener
    All Known Implementing Classes:
    SingleArgumentMethodEventListener

    public interface EventListener
    An event listener knows how to accept and process events of a particular type (or types).

    Note that this interface is in the event implementation support package (and not the event package directly) because it is a supporting concept for event bus implementations and not something that most application developers using Shiro should implement directly. App developers should instead use the Subscribe annotation on methods they wish to receive events.

    This interface therefore mainly represents a 'middle man' between the event bus and the actual subscribing component. As such, event bus implementors (or framework/infrastructural implementors) or those that wish to customize listener/dispatch functionality might find this concept useful.

    It is a concept almost always used in conjunction with a EventListenerResolver implementation.

    Since:
    1.3
    See Also:
    SingleArgumentMethodEventListener, AnnotationEventListenerResolver
    • Method Detail

      • accepts

        boolean accepts​(Object event)
        Returns true if the listener instance can process the specified event object, false otherwise.
        Parameters:
        event - the event object to test
        Returns:
        true if the listener instance can process the specified event object, false otherwise.
      • onEvent

        void onEvent​(Object event)
        Handles the specified event. Again, as this interface is an implementation concept, implementations of this method will likely dispatch the event to a 'real' processor (e.g. method).
        Parameters:
        event - the event to handle.