Package com.atlassian.event.internal

Class EventPublisherImpl

java.lang.Object

com.atlassian.event.internal.EventPublisherImpl

All Implemented Interfaces:

EventListenerRegistrar, EventPublisher

@ThreadSafe
public final class EventPublisherImpl
extends Object
implements EventPublisher

The default implementation of the EventPublisher interface.

One can customise the event listening by instantiating with custom listener handlers and the event dispatching through EventDispatcher.

See the com.atlassian.event.spi package for more information.

Since:

2.0

See Also:

• ListenerHandler
• EventDispatcher

Constructor Summary

Constructors

Constructor	Description
EventPublisherImpl(EventDispatcher eventDispatcher, ListenerHandlersConfiguration configuration)
EventPublisherImpl(EventDispatcher eventDispatcher, ListenerHandlersConfiguration listenerHandlersConfiguration, InvokerTransformer transformer)	If you need to customise the asynchronous handling, you should use the AsynchronousAbleEventDispatcher together with a custom executor.

Method Summary

Modifier and Type	Method	Description
void	publish(Object event)	Publish an event that will be consumed by all listeners which have registered to receive it.
void	register(Object listener)	Register a listener to receive events.
void	unregister(Object listener)	Un-register a listener so that it will no longer receive events.
void	unregisterAll()	Un-register all listeners that this registrar knows about.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

EventPublisherImpl

public EventPublisherImpl(EventDispatcher eventDispatcher,
 ListenerHandlersConfiguration configuration)

EventPublisherImpl

public EventPublisherImpl(EventDispatcher eventDispatcher,
 ListenerHandlersConfiguration listenerHandlersConfiguration,
 InvokerTransformer transformer)

If you need to customise the asynchronous handling, you should use the AsynchronousAbleEventDispatcher together with a custom executor.

You might also want to have a look at using the EventThreadFactory to keep the naming of event threads consistent with the default naming of the Atlassian Event library.

Parameters:

eventDispatcher - the event dispatcher to be used with the publisher

listenerHandlersConfiguration - the list of listener handlers to be used with this publisher

transformer - the batcher for batching up listener invocations

See Also:

• AsynchronousAbleEventDispatcher
• EventThreadFactory

Method Details

publish

public void publish(@Nonnull
 Object event)

Description copied from interface: EventPublisher

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). 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.

Specified by:

publish in interface EventPublisher

Parameters:

event - the event to publish

register

public void register(@Nonnull
 Object listener)

Description copied from interface: EventListenerRegistrar

Register a listener to receive events.

All implementations must support registration of listeners where event handling methods are indicated by the EventListener annotation.

Specified by:

register in interface EventListenerRegistrar

Parameters:

listener - The listener that is being registered

See Also:

• annotation which can be used to indicate event listener methods

unregister

public void unregister(@Nonnull
 Object listener)

Description copied from interface: EventListenerRegistrar

Un-register a listener so that it will no longer receive events.

If the given listener is not registered, nothing will happen.

Specified by:

unregister in interface EventListenerRegistrar

Parameters:

listener - The listener to un-register

unregisterAll

public void unregisterAll()

Description copied from interface: EventListenerRegistrar

Un-register all listeners that this registrar knows about.

Specified by:

unregisterAll in interface EventListenerRegistrar