Codename One WebSocket + Spring Boot - codenameone

Question

About the Codename One Websocket cn1lib, I saw your lesson on the Whatsapp clone, however the code you proposed is for a complete app. Could you provide a simpler self-enclosed example of use of Websocket cn1lib with client-side code (Codename One code to send and receive messages) and server-side code (Spring Boot Java 8 to receive and send messages)?
I’m particulary interested in a simple Spring Boot example that interacts with Codename One, as start point to better understand and learn websocket.
Thank you

Answer 1

It would look roughly like this on the server:
public class WebSocketServer extends TextWebSocketHandler {
private static final Object LOCK = new Object();
private Map<String, WebSocketSession> sessions = new HashMap<>();
#Override
protected void handleTextMessage(WebSocketSession session,
TextMessage message) throws Exception {
Gson gson = new Gson();
MyDTO parsed = gson.fromJson(message.getPayload(), MyDTO.class);
// ... do stuff with incoming message
synchronized(LOCK) {
if(!sessions.contains(parsed.getId()) {
sessions.put(parsed.getId(), session);
}
}
}
public boolean sendMessage(String destId, String json) {
Session s = null;
synchronized(LOCK) {
s = sessions.get(destId);
}
if (s != null && s.isOpen()) {
try {
s.sendMessage(new TextMessage(s));
return true;
} catch (IOException e) {
synchronized(LOCK) {
sessions.remove(destId);
}
}
}
return false;
}
}