autobahn-spring: Autobahn|Java and Spring

Are you an enthusiastic user of Spring and do you also want to benefit from the Web Application Messaging Protocol? Even though wamp2spring mainly serves as a router, Spring users often want to create several microservices communicating with each other. A comfortable solution is using the WAMP library Autobahn|Java. This article will describe how to combine Spring and Autobahn|Java.

Create a Controller for WAMP

Autobahn|Java could be implemented as a controller. Therefore, the bean of Spring should be created with the annotation @Controller. Topics and procedures could be handled exactly as described in the article about Autobahn|Java. The methods implementing this should be registered as listeners. This could be achieved in the constructor of the controller.

 1public WampController() {
 2
 3    this.executor = Executors.newSingleThreadExecutor();
 4    this.session = new Session(executor);
 5
 6    session.addOnJoinListener(this::registerExample);
 7    session.addOnJoinListener(this::callExample);
 8    session.addOnJoinListener(this::subscribeExample);
 9    session.addOnJoinListener(this::publishExample);
10}

The main difference between using the raw Jetty-based library and implementing Autobahn|Java as a Spring bean is that the controller starts automatically after the object gets created. In Spring, this could be realised with the annotation @PostConstruct. A method annotated like this gets executed automatically after the object gets instantiated. This method for starting the controller would try to connect to the router.

 1@PostConstruct
 2public void start() {
 3
 4    Client client = new Client(session, url, realm, executor);
 5    try {
 6        client.connect().get();
 7    } catch (Exception e) {
 8        e.printStackTrace();
 9    }
10}

Run the Application

To run the whole application, the main method and the annotation @SpringBootApplication have to be added. This could be done either in the same class or in a separate one.

1@SpringBootApplication
2public class AutobahnSpringApplication {
3
4    public static void main(String[] args) {
5        SpringApplication.run(AutobahnSpringApplication.class, args);
6    }
7}

To see the whole project, have a look at my GitHub page.