org.seedstack.business.domain.DomainEvent Maven / Gradle / Ivy
/*
* Copyright © 2013-2024, The SeedStack authors
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
package org.seedstack.business.domain;
/**
* A domain event is used to represent something that happened in the domain. It happened in the
* past and is of interest to the business.
*
* A domain event always represent something that happened in the past. Its name must be in the
* past tense and be based upon the ubiquitous language.
A domain event can be as little as
* just a name. More often, it will contain values and identifiers that represent the relevant state
* at the time the event happened. That state should be minimized and the receivers should query the
* model to access additional information if necessary.
*
* As they represent something in the past, domain events must be immutable. As such they can
* only contain immutable objects like value objects, primitive types, strings, etc…
*
* Domain events are first and foremost about communication, within the system but also with
* other systems. A domain event should therefore be kept as simple as possible as be easy to
* serialize.
*
* Example:
*
* public class SomeDomainEvent implements DomainEvent {
* private String attribute1;
* private String attribute2;
*
* public SomeDomainEvent(String attribute1, String attribute2) {
* this.attribute1 = attribute1;
* this.attribute2 = attribute2;
* }
*
* {@literal @}Override
* public int hashCode() {
* // implement based on all attributes
* }
*
* {@literal @}Override
* public boolean equals() {
* // implement based on all attributes
* }
*
* // Other methods
* }
*
*
* @see DomainEventHandler
* @see DomainEventPublisher
* @see DomainEventInterceptor
* @see ValueObject
*/
public interface DomainEvent extends ValueObject {
}