Sample event used with our Spring Boot/RabbitMQ solution

1 EmailUpdated.java

import lombok.Value;

// This code only works if compiling the code using javac's -parameters option (Java 8 only).
// With this option, Jackons can use the all-args constructor of our type.
// See https://gist.github.com/ndemengel/72f362bc31afe5fcaa0499af8f269651 for a more general solution.
@Value
public class EmailUpdated implements Event {

    public static final String EXCHANGE_NAME = "email.updated.exchange";

    String accountId;
    String oldEmail;
    String newEmail;
}

2 AccountSettingsController.java

@RequestMapping(path = "/some/path", method = POST)
public ModelAndView updateEmail(@Valid NewEmailForm form) {
    // ...
    // call some account-handling service which ultimately does the following:
    eventsService.fire(new EmailUpdated(accountId, oldEmail(), newEmail));
    // ...
}

3 MailChimpSynchronization.java

@RabbitEventListener(queue = "email.updated.mailchimp.queue")
public void emailUpdated(EmailUpdated event) {
    updateMailChimpMember(event.getOldEmail(), event.getNewEmail());
}

4 Event.java

// just a marker interface
public interface Event {}

5 EventsService.java

// just a single fire method defined once and for all, no more overloads
public void fire(Event event) {
    String exchangeName = obtainTheExchangeNameInSomeWay(event);
    rabbitTemplate.convertAndSend(exchangeName, event);
}