org.axonframework.eventhandling

Interface EventBus

All Superinterfaces:

StreamableMessageSource<TrackedEventMessage<?>>, SubscribableMessageSource<EventMessage<?>>

All Known Subinterfaces:

EventStore

All Known Implementing Classes:

AbstractEventBus, AbstractEventStore, EmbeddedEventStore, SimpleEventBus

public interface EventBus
extends SubscribableMessageSource<EventMessage<?>>, StreamableMessageSource<TrackedEventMessage<?>>

Specification of the mechanism on which the Event Listeners can subscribe for events and event publishers can publish their events. The event bus dispatches events to all subscribed listeners.

Implementations may or may not dispatch the events to event listeners in the dispatching thread.

Since:

0.1

Author:

Allard Buijze

See Also:

EventListener, SimpleEventBus

Method Summary

Modifier and Type	Method and Description
TrackingEventStream	openStream(TrackingToken trackingToken) Open an event stream containing all events since given tracking token.
default void	publish(EventMessage<?>... events) Publish a collection of events on this bus (one, or multiple).
void	publish(List<? extends EventMessage<?>> events) Publish a collection of events on this bus (one, or multiple).
Registration	registerDispatchInterceptor(MessageDispatchInterceptor<EventMessage<?>> dispatchInterceptor) Register the given interceptor with this bus.

Methods inherited from interface org.axonframework.messaging.SubscribableMessageSource

subscribe

Method Detail

openStream

TrackingEventStream openStream(TrackingToken trackingToken)

Open an event stream containing all events since given tracking token. The returned stream is comprised of events from aggregates as well as other application events. Pass a trackingToken of null to open a stream containing all available events. Note that the returned stream is infinite, so beware of applying terminal operations to the returned stream.

In case the event bus cannot open a stream for a given tracking token, for instance because the event bus does not persist or cache events, the event bus will throw an UnsupportedOperationException.

Specified by:

openStream in interface StreamableMessageSource<TrackedEventMessage<?>>

Parameters:

trackingToken - object describing the previous position in the stream or null to create a stream of all events

Returns:

a TrackingEventStream with events since the given trackingToken

Throws:

UnsupportedOperationException - in case this event bus does not support streaming from given token

publish

default void publish(EventMessage<?>... events)

Publish a collection of events on this bus (one, or multiple). The events will be dispatched to all subscribed listeners.

Implementations may treat the given events as a single batch and distribute the events as such to all subscribed EventListeners.

Parameters:

events - The collection of events to publish

publish

void publish(List<? extends EventMessage<?>> events)

Publish a collection of events on this bus (one, or multiple). The events will be dispatched to all subscribed listeners.

Implementations may treat the given events as a single batch and distribute the events as such to all subscribed EventListeners.

Parameters:

events - The collection of events to publish

registerDispatchInterceptor

Registration registerDispatchInterceptor(MessageDispatchInterceptor<EventMessage<?>> dispatchInterceptor)

Register the given interceptor with this bus. When subscribed it will intercept any event messages published on this bus.

If the given interceptor is already registered, nothing happens.

Parameters:

dispatchInterceptor - The event message dispatch interceptor to register

Returns:

a handle to unregister the dispatchInterceptor. When unregistered it will no longer be given event messages published on this bus.