Example for @DomainEvents and @AfterDomainEventsPublication

Question

I have encountered the @DomainEvents and @AfterDomainEventsPublication annotation in spring Data JPA Reference Documentation. But I am not able to find the perfect example to explain about these annotaions

Answer 1

You can see sample in the original unit tests for EventPublishingRepositoryProxyPostProcessor EventPublishingRepositoryProxyPostProcessorUnitTests.java by Oliver Gierke in GitHub Repository of Spring Data Commons.

Description in base issue of Spring Jira DATACMNS-928 Support for exposing domain events from aggregate roots as Spring application events was useful for me.

UPDATE

This is simple and really working example by Zoltan Altfatter: Publishing domain events from aggregate roots

Answer 2

Here is my example code:

package com.peaceelite.humanService;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import org.springframework.data.domain.AfterDomainEventPublication;
import org.springframework.data.domain.DomainEvents;
import java.util.*;

@Entity
public class SalesmanCustomerRelationship{


@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;

private String firstName;
private String lastName;


/*getters & setters*/

@DomainEvents
Collection<Object> domainEvents() {
    List<Object> result = new ArrayList<Object>();
    result.add("Here should be an Event not a String, but, anyway");
    return result;
}

@AfterDomainEventPublication 
void callbackMethod() {
    System.out.println("DATA SAVED!\n"+"WELL DONE");
}

}

This is an entity class managed by a spring data repository. Both @DomainEvents and @AfterDomainEventPublication happens after CrudRepository.save() being executed. One thing that is interesting is that @AfterDomainEventPublication ONLY works when @DomainEvents exists.

I'm learning Spring Data reference too, both this question and Dmitry Stolbov's answer helped me a lot.