We have a new sample room written in Java with the Spring framework:

• sample-room-spring
• the room up and running

This post is a brief overview of the creation process.

Jumpstart with code gen

Using this guide, we made a Spring microservice starter that could be deployed to Bluemix with just a few commands:

{% highlight shell_session %} $ bx dev create ? Select a pattern:

1. Web App
2. Mobile App
3. Backend for Frontend
4. Microservice
5. MFP Enter a number> 4

? Select a starter:

1. Basic Enter a number> 1

? Select a language:

1. Java - MicroProfile / Java EE
2. Node
3. Python
4. Java - Spring Framework Enter a number> 4

? Enter a name for your project> springmsdemo
? Enter a hostname for your project> springmsdemo ? Do you want to add services to your project? [y/n]> y

? Select a service:

1. Cloudant NoSQL Database
2. Object Storage Enter a number> 1

? Select a service plan:

1. Lite
2. Standard
3. Dedicated Hardware Enter a number> 1

Successfully added service to project.

? Do you want to add another service? [y/n]> n

The project, springmsdemo, has been successfully saved into the current directory. OK {% endhighlight %}

Time to fill in our own code!

Borrowing from the Java room

The Java room had a lot of code we could reuse, so that's what we did.

Notable differences:

• We needed a WebSocketConfig to map our SocketHandler to /room WebSocketConfig to map our SocketHandler to /room

{% highlight java linenos %} @Configuration @EnableWebSocket class WebSocketConfig implements WebSocketConfigurer {

  @Inject
  SocketHandler handler;

  public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
      registry.addHandler(handler, "/room");
  }

} {% endhighlight %}

• We also needed to use a Spring WebSocket (org.springframework.web.socket.WebSocketSession) instead of the standard one (javax.websocket.Session). It looks roughly like this (simplified): (org.springframework.web.socket.WebSocketSession) instead of the standard one (javax.websocket.Session). It looks roughly like this (simplified):

{% highlight java linenos %} @Component public class SocketHandler extends TextWebSocketHandler {

  private final HashMap<String, WebSocketSession> sessions = new HashMap<>();
  @Inject
  private RoomImplementation roomImplementation;

  @Override
  public void afterConnectionEstablished(WebSocketSession session) throws Exception {
      sessions.put(session.getId(), session);
      session.sendMessage(new TextMessage(Message.ACK_MSG.toString()));
  }

  @Override
  public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
      sessions.remove(session.getId());
      Log.log(Level.INFO, this, "WebSocketSession with Id (" + session.getId() + ") closed with reason: " + status.getReason());
  }

  @Override
  public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
      roomImplementation.handleMessage(new Message(message.getPayload().toString()), this);
  }

  public void sendMessage(Message message) {
      for (WebSocketSession s : sessions.values()) {
          sendMessageToSession(s, message);
      }
  }

  private boolean sendMessageToSession(WebSocketSession session, Message message) {
      try {
          session.sendMessage(new TextMessage(message.toString()));
          return true;
      } catch (IOException e) {
          ...
      }
  }
  
  ...

} {% endhighlight %}

After porting some common code, we can run mvn spring-boot:run to see our Spring room running locally!

Deploying to Bluemix

After adding Travis, Docker, and JaCoCo, we were ready to deploy to Bluemix:

bx dev build

then

bx dev deploy

and our room is deployed as a Cloud Foundry service with a reachable endpoint!

Registering the room with Game On!

Done!

/teleport spring-sample