org.axonframework.domain
Class DomainEvent

java.lang.Object
  org.axonframework.domain.EventBase
      org.axonframework.domain.DomainEvent

All Implemented Interfaces:

Serializable, Event

Direct Known Subclasses:

AggregateSnapshot

public abstract class DomainEvent
extends EventBase

Base class for all Domain Events. This class contains the basic behavior expected from any event to be processed by event sourcing engines and aggregates.

Since:

0.1

Author:

Allard Buijze

See Also:

Serialized Form

Constructor Summary

protected	DomainEvent() Initialize the domain event.
protected	DomainEvent(long sequenceNumber, AggregateIdentifier aggregateIdentifier) Initialize the domain event.

Method Summary

boolean	equals(Object o) Checks for equality of two events.
AggregateIdentifier	getAggregateIdentifier() Returns the identifier of the aggregate that reported this event.
Long	getAggregateVersion() Returns the version number of the aggregate generating this event.
Long	getSequenceNumber() Returns the sequence number of this event, if available.
int	hashCode()

Methods inherited from class org.axonframework.domain.EventBase

addMetaData, getEventIdentifier, getEventRevision, getMetaData, getMetaDataValue, getTimestamp, setEventRevision

Methods inherited from class java.lang.Object

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

Constructor Detail

DomainEvent

protected DomainEvent()

Initialize the domain event. Will set the current time stamp and generate a random event identifier. Use this constructor when using the AbstractEventSourcedAggregateRoot.apply(DomainEvent) method. The sequenceNumber and aggregateIdentifier are automatically set to the correct values for that aggregate.

If you do not use the AbstractEventSourcedAggregateRoot.apply(DomainEvent) method, but need the sequenceNumber and aggregateIdentifier to be set to specific values, use the DomainEvent(long, AggregateIdentifier) constructor.

DomainEvent

protected DomainEvent(long sequenceNumber,
                      AggregateIdentifier aggregateIdentifier)

Initialize the domain event. Will set the current time stamp and generate a random event identifier. Use this constructor when you need the sequenceNumber and aggregateIdentifier to be set to specific values.

Two use cases for this constructor are

• the generation of events when not using event sourcing
• the generation of snapshot events.

When creating a DomainEvent using this constructor, all calls to setAggregateIdentifier(AggregateIdentifier) and setSequenceNumber(long) will result in an exception.

Parameters:

sequenceNumber - The sequence number to assign to this event

aggregateIdentifier - The identifier of the aggregate this event applies to

Method Detail

getSequenceNumber

public Long getSequenceNumber()

Returns the sequence number of this event, if available. Will return null if this event has not been added to an EventContainer.

Returns:

the sequence number of this event, or null if unknown.

getAggregateVersion

public Long getAggregateVersion()

Returns the version number of the aggregate generating this event. This method returns the same value as getSequenceNumber() and is solely provided to provide a clear meaning to the returned value.

Returns:

the version number of the aggregate generating this event.

getAggregateIdentifier

public AggregateIdentifier getAggregateIdentifier()

Returns the identifier of the aggregate that reported this event.

Returns:

the identifier of the aggregate that reported this event

equals

public boolean equals(Object o)

Checks for equality of two events. Two events are equal when they have the same type, aggregate identifier, time stamp and sequence number. This allows to test for equality after one or more instances have been serialized and deserialized.

Overrides:

equals in class EventBase

Parameters:

o - the other DomainEvent

Returns:

true when equals, otherwise false

hashCode

public int hashCode()

Overrides:

hashCode in class EventBase