org.axonframework.domain

Class EventContainer

java.lang.Object

org.axonframework.domain.EventContainer

All Implemented Interfaces:

Serializable

public class EventContainer
extends Object
implements Serializable

Container for events related to a single aggregate. The container will wrap registered event (payload) and metadata in an DomainEventMessage and automatically assign the aggregate identifier and the next sequence number.

The EventContainer also takes care of the invocation of EventRegistrationCallbacks once events are registered with this aggregate for publication.

This implementation is not thread safe and should only be used with proper locking in place. Generally, only a single thread will be modifying an aggregate at any given time.

Since:

0.1

Author:

Allard Buijze

See Also:

DomainEventMessage, AbstractAggregateRoot, Serialized Form

Constructor Summary

Constructors

Constructor and Description
EventContainer(Object aggregateIdentifier) Initialize an EventContainer for an aggregate with the given aggregateIdentifier.

Method Summary

Methods

Modifier and Type	Method and Description
<T> DomainEventMessage<T>	addEvent(MetaData metaData, T payload) Add an event to this container.
void	addEventRegistrationCallback(EventRegistrationCallback eventRegistrationCallback) Adds an EventRegistrationCallback, which is invoked when the aggregate owning this container registers an Event.
void	commit() Clears the events in this container.
Object	getAggregateIdentifier() Returns the aggregate identifier assigned to this container.
List<DomainEventMessage>	getEventList() Returns an unmodifiable version of the backing list of events.
DomainEventStream	getEventStream() Read the events inside this container using a DomainEventStream.
Long	getLastCommittedSequenceNumber() Returns the sequence number of the last committed event, or null if no events have been committed.
Long	getLastSequenceNumber() Returns the sequence number of the event last added to this container.
void	initializeSequenceNumber(Long lastKnownSequenceNumber) Sets the first sequence number that should be assigned to an incoming event.
int	size() Returns the number of events currently inside this container.

Methods inherited from class java.lang.Object

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

Constructor Detail

EventContainer

public EventContainer(Object aggregateIdentifier)

Initialize an EventContainer for an aggregate with the given aggregateIdentifier. This identifier will be attached to all incoming events.

Parameters:

aggregateIdentifier - the aggregate identifier to assign to this container

Method Detail

addEvent

public <T> DomainEventMessage<T> addEvent(MetaData metaData,
                                 T payload)

Add an event to this container.

Events should either be already assigned to the aggregate with the same identifier as this container, or have no aggregate assigned yet. If an event has a sequence number assigned, it must follow directly upon the sequence number of the event that was previously added.

Type Parameters:

T - the type of payload contained in the event

Parameters:

metaData - the metaData of the event to add to this container

payload - the payload of the event to add to this container

Returns:

the DomainEventMessage added to the container

getEventStream

public DomainEventStream getEventStream()

Read the events inside this container using a DomainEventStream. The returned stream is a snapshot of the uncommitted events in the aggregate at the time of the invocation. Once returned, newly applied events are not accessible from the returned event stream.

Returns:

a DomainEventStream providing access to the events in this container

getAggregateIdentifier

public Object getAggregateIdentifier()

Returns the aggregate identifier assigned to this container.

Returns:

the aggregate identifier assigned to this container

initializeSequenceNumber

public void initializeSequenceNumber(Long lastKnownSequenceNumber)

Sets the first sequence number that should be assigned to an incoming event.

Parameters:

lastKnownSequenceNumber - the sequence number of the last known event

getLastSequenceNumber

public Long getLastSequenceNumber()

Returns the sequence number of the event last added to this container.

Returns:

the sequence number of the last event

getLastCommittedSequenceNumber

public Long getLastCommittedSequenceNumber()

Returns the sequence number of the last committed event, or null if no events have been committed.

Returns:

the sequence number of the last committed event

commit

public void commit()

Clears the events in this container. The sequence number is not modified by this call.

size

public int size()

Returns the number of events currently inside this container.

Returns:

the number of events in this container

getEventList

public List<DomainEventMessage> getEventList()

Returns an unmodifiable version of the backing list of events.

Returns:

a list containing the events in this container

addEventRegistrationCallback

public void addEventRegistrationCallback(EventRegistrationCallback eventRegistrationCallback)

Adds an EventRegistrationCallback, which is invoked when the aggregate owning this container registers an Event. These callbacks are cleared when the Events are committed.

Parameters:

eventRegistrationCallback - The callback to notify when an Event is registered.