com.atlassian.event.api

Interface EventPublisher

All Superinterfaces:

EventListenerRegistrar

All Known Implementing Classes:

EventPublisherImpl, LockFreeEventPublisher

public interface EventPublisher
extends EventListenerRegistrar

Interface to publish events. It allows the decoupling of listeners which handle events and publishers which dispatch events.

Since:

2.0

See Also:

annotation which can be used to indicate event listener methods

Method Summary

Modifier and Type	Method and Description
void	publish(Object event) Publish an event that will be consumed by all listeners which have registered to receive it.

Methods inherited from interface com.atlassian.event.api.EventListenerRegistrar

register, unregister, unregisterAll

Method Detail

publish

void publish(@Nonnull
             Object event)

Publish an event that will be consumed by all listeners which have registered to receive it. Implementations must dispatch events to listeners which have a public method annotated with EventListener and one argument which is assignable from the event type (i.e. a superclass or interface implemented by the event object). Implementations may also dispatch events to legacy EventListener implementations based on the types returned from EventListener.getHandledEventClasses(). This method should process all event listeners, despite any errors or exceptions that are generated as a result of dispatching the event.

Default order

The order in which registered listeners are invoked is predictable. Listeners will be invoked for listeners registered on the object itself, then listeners on the parent class, then the grandparent and so on until finally all listeners for java.lang.Object are invoked.

After walking the class hierarchy the interface listeners are invoked, again from the most specific interface first. Note that the ordering within a specific event type is not guaranteed. If there are multiple registered listeners for IssueEvent, then they will be invoked in the order of registration. It is however guaranteed that a listener for IssueEvent will be invoked before a listener for Event

Custom order

The default order can be overridden with EventListener.order(). Event listeners with order defined are overriding default rules and will be processed in ascending order of the EventListener.order() value. Default ordering is preserved when processing event listeners with the same EventListener.order() value. There is a soft rule for plugin event listeners to use order values in range [-1000, 1000] if needed. Values in following ranges: [Integer.MIN_VALUE, -1000) and (1000, Integer.MAX_VALUE] are reserved for Atlassian product internal event listeners.

Parameters:

event - the event to publish

Throws:

NullPointerException - if the event is null