Spring websockets - Separating MessageMapping and SendTo

Question

I stuck with following issue on websockets in spring 4, not sure why this code:

@MessageMapping("/hello")
@SendTo("/topic/greetings")
public Greeting greeting(HelloMessage message) throws Exception {
    Thread.sleep(3000); 
    return new Greeting("Hello, " + message.getName() + "!");
}

works fine, and why this does not:

@MessageMapping("/hello")
public void hehe(HelloMessage message){
    try {
        greeting(message);
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
} 
@SendTo("/topic/greetings")
public Greeting greeting(HelloMessage message) throws Exception {
    Thread.sleep(3000); 
    return new Greeting("Hello, " + message.getName() + "!");
}

I'm looking for solution how to call greeting() method if an event on server side occurred.

Answer 1

Separating them out will not work!!

@MessageMapping("/hello")
@SendTo("/topic/greetings")
public Greeting greeting(HelloMessage message) throws Exception {
    Thread.sleep(3000); 
    return new Greeting("Hello, " + message.getName() + "!");
}

On a server side event if you want to send to a destination, you should be using:

simpMessagingTemplate.convertAndSend("/user/" + username + "/topic/greetings", 
       new Greeting("Hello, " + message.getName() + "!"));
// username should refer to the user in socket header if you want to send to a specific user
// omit the prefix /user/<username> if you are broadcasting

where SIMP is used (you can use messaging uitlities like rabbitMQ too):

@Autowired
org.springframework.messaging.simp.SimpMessagingTemplate simpMessagingTemplate;