Redisson async procesing messages

Question

I'm trying to aply Redisson features for my project as message broker and I have a question. Is it possible to push Redisson to precceding recieved messages asynchronously? I have created a small example, sent 4 messages from different URL's. I expected, that Redisson proceeded them asynchronously, but it did it one by one. Here the implementation:

public class RedisListenerServiceImpl implements MessageListener<String> {

    private static final Logger log = LoggerFactory.getLogger(RedisListenerServiceImpl.class);
    private final ObjectMapper objectMapper = new ObjectMapper();

    @Override
    public void onMessage(CharSequence channel, String stringMsg) {

        log.info("Message received: {}", stringMsg);
        MessageDto msg;
        try {
            msg = objectMapper.readValue(stringMsg, MessageDto.class);
        } catch (final IOException e) {
            log.error("Unable to deserialize message: {}", e.getMessage(), e);
            return;
        }

        try {
            //Do my stuff
        } catch (Exception e) {
            log.error("Unable to get service from factory: {}", e.getMessage(), e);
        }

    }
}

And the config:

@Configuration
public class RedisListenerConfig {

    @Autowired
    public RedisListenerConfig(RedissonClient redisClient,
                               MessageListener redisListenerService,
                               @Value("${redis.sub.key}") String redisSubKey) {

        RTopic subscribeTopic = redisClient.getTopic(redisSubKey);
        subscribeTopic.addListenerAsync(String.class, redisListenerService);
    }
}

hey, may it help - take a look at the multithreaded example https://stackoverflow.com/questions/66485053/question-about-the-executors-newsinglethreadexecutor/66485130#66485130 — aran, Mar 14 '21 at 15:05

score 2 · Accepted Answer · answered Mar 13 '21 at 01:47

It's expected behavior. If you want your messages to be processed concurrently when the Listener onMessage() method is triggered, just use a thread pool to process it.

Since Redisson doesn't know how many threads you want to consume the triggered events, it leaves the implementation detail to you.

public class RedisListenerServiceImpl implements MessageListener<String> {

private static final Logger log = LoggerFactory.getLogger(RedisListenerServiceImpl.class);
private final ObjectMapper objectMapper = new ObjectMapper();
private final ExecutorService executorService = Executors.newFixedThreadPool(10);

@Override
public void onMessage(CharSequence channel, String stringMsg) {

    log.info("Message received: {}", stringMsg);
    MessageDto msg;
    try {
        msg = objectMapper.readValue(stringMsg, MessageDto.class);
        executorService.submit(()->{
        System.out.println("do something with message: "+msg);
    });
    } catch (final IOException e) {
        log.error("Unable to deserialize message: {}", e.getMessage(), e);
        return;
    }

    try {
        //Do my stuff
    } catch (Exception e) {
        log.error("Unable to get service from factory: {}", e.getMessage(), e);
    }

}

Thanks for explanation. But if async doesn't mean process messages concurrently, what does it mean? — Данила Кононихин, Mar 14 '21 at 06:43
@ДанилаКононихин I think here 'async' means non-blockingly. There's a background listener thread monitoring the event for you. It doesn't mean therer are multiple listener threads processing the events concurrently. — AwesomeHunter, Mar 14 '21 at 17:28

Redisson async procesing messages

1 Answers1