io.nats.client.MessageHandler Java Examples

public void subscribe(String subject, String queue, MessageHandler handler) throws Exception {

        if (subject == null)
            return;

        synchronized (pluginLock) {
            logger.debug("Plugin subscribe to '{}', queue '{}'.", subject,
                    (queue == null ? "(none)" : queue));

            // do not subscribe twice.
            if (subscriptions.containsKey(subject)) {
                logger.debug("Subscription already exists.");
                return;
            }

            AsyncSubscription s;

            if (queue == null)
                s = connection.subscribe(subject, handler);
            else
                s = connection.subscribe(subject, queue, handler);

            subscriptions.put(subject, s);
        }
    }
 

public void subscribe(String subject, String queue, MessageHandler handler) throws Exception {

        if (subject == null)
            return;

        synchronized (pluginLock) {
            logger.debug("Plugin subscribe to '{}', queue '{}'.", subject,
                    (queue == null ? "(none)" : queue));

            // do not subscribe twice.
            if (subscriptions.containsKey(subject)) {
                logger.debug("Subscription already exists.");
                return;
            }

            AsyncSubscription s;

            if (queue == null)
                s = connection.subscribe(subject, handler);
            else
                s = connection.subscribe(subject, queue, handler);

            subscriptions.put(subject, s);
        }
    }
 

private void testConnectorAPIs() throws Exception {
    MessageHandler mh = new MessageHandler() {
        @Override
        public void onMessage(Message message) {
            ;;
        }
    };

    // test various combinatitions of subscribes and unsubscribes.
    connector.subscribe("foo1");
    connector.subscribe("foo1");

    connector.subscribe("foo2", mh);
    connector.subscribe("foo2", mh);

    connector.subscribe("foo3", "qg1");
    connector.subscribe("foo3", "qg1");

    connector.subscribe("foo4", "qg1", mh);
    connector.unsubscribe("foo1");
    connector.unsubscribe("foo2");
    connector.unsubscribe("foo3");

    connector.unsubscribe("foo4");
    connector.unsubscribe("foo4");

    connector.unsubscribe("unknown");
    connector.unsubscribe(null);

    connector.flush();

    Connection c = connector.getConnection();
    if (c == null)
        throw new Exception("Expected a valid connection.");

    ConnectionFactory cf = connector.getConnectionFactory();
    if (cf == null)
        throw new Exception("Expected a valid connection.");
}
 

private void testConnectorAPIs() throws Exception {
    MessageHandler mh = new MessageHandler() {
        @Override
        public void onMessage(Message message) {
            ;;
        }
    };

    // test various combinatitions of subscribes and unsubscribes.
    connector.subscribe("foo1");
    connector.subscribe("foo1");

    connector.subscribe("foo2", mh);
    connector.subscribe("foo2", mh);

    connector.subscribe("foo3", "qg1");
    connector.subscribe("foo3", "qg1");

    connector.subscribe("foo4", "qg1", mh);
    connector.unsubscribe("foo1");
    connector.unsubscribe("foo2");
    connector.unsubscribe("foo3");

    connector.unsubscribe("foo4");
    connector.unsubscribe("foo4");

    connector.unsubscribe("unknown");
    connector.unsubscribe(null);

    connector.flush();

    Connection c = connector.getConnection();
    if (c == null)
        throw new Exception("Expected a valid connection.");

    ConnectionFactory cf = connector.getConnectionFactory();
    if (cf == null)
        throw new Exception("Expected a valid connection.");
}
 

public Dispatcher createDispatcher(MessageHandler handler) {
    if (isClosed()) {
        throw new IllegalStateException("Connection is Closed");
    } else if (isDraining()) {
        throw new IllegalStateException("Connection is Draining");
    }

    NatsDispatcher dispatcher = new NatsDispatcher(this, handler);
    String id = this.nuid.next();
    this.dispatchers.put(id, dispatcher);
    dispatcher.start(id);
    return dispatcher;
}
 

NatsDispatcher(NatsConnection conn, MessageHandler handler) {
    super(conn);
    this.defaultHandler = handler;
    this.incoming = new MessageQueue(true);
    this.subscriptionsUsingDefaultHandler = new ConcurrentHashMap<>();
    this.subscriptionsWithHandlers = new ConcurrentHashMap<>();
    this.subscriptionHandlers = new ConcurrentHashMap<>();
    this.running = new AtomicBoolean(false);
    this.waitForMessage = Duration.ofMinutes(5); // This can be long since we aren't doing anything
}
 

public Subscription subscribe(String subject, MessageHandler handler) {
    if (subject == null || subject.length() == 0) {
        throw new IllegalArgumentException("Subject is required in subscribe");
    }

    if (handler == null) {
        throw new IllegalArgumentException("MessageHandler is required in subscribe");
    }
    return this.subscribeImpl(subject, null, handler);
}
 

public Subscription subscribe(String subject, String queueName,  MessageHandler handler) {
    if (subject == null || subject.length() == 0) {
        throw new IllegalArgumentException("Subject is required in subscribe");
    }

    if (queueName == null || queueName.length() == 0) {
        throw new IllegalArgumentException("QueueName is required in subscribe");
    }

    if (handler == null) {
        throw new IllegalArgumentException("MessageHandler is required in subscribe");
    }
    return this.subscribeImpl(subject, queueName, handler);
}
 

@Test(expected=IllegalArgumentException.class)
public void testThrowOnNullHandler() throws IOException, InterruptedException, TimeoutException {
    try (NatsTestServer ts = new NatsTestServer(false);
                Connection nc = Nats.connect(ts.getURI())) {
        Dispatcher d = nc.createDispatcher((msg) -> {});
        d.subscribe("test", (MessageHandler)null);
        assertFalse(true);
    }
}
 

@Test(expected=IllegalArgumentException.class)
public void testThrowOnNullHandlerWithQueue() throws IOException, InterruptedException, TimeoutException {
    try (NatsTestServer ts = new NatsTestServer(false);
                Connection nc = Nats.connect(ts.getURI())) {
        Dispatcher d = nc.createDispatcher((msg) -> {});
        d.subscribe("test", "queue", (MessageHandler)null);
        assertFalse(true);
    }
}
 

public void subscribe(String subject, MessageHandler handler) throws Exception {
    subscribe(subject, null, handler);
}
 

public void subscribe(String subject, MessageHandler handler) throws Exception {
    subscribe(subject, null, handler);
}
 

/***
 * Adds interest in a NATS subject, with a custom handle.
 * @param subject - subject of interest.
 * @param handler - message handler
 * @throws Exception - an error occurred in the subsciption process.
 */
public void subscribe(String subject, MessageHandler handler) throws Exception;
 

/***
 * Adds interest in a NATS subject with a queue group, with a custom handler.
 * @param subject - subject of interest.
 * @param queue - work queue
 * @param handler - message handler
 * @throws Exception - an error occurred in the subsciption process.
 */
public void subscribe(String subject, String queue, MessageHandler handler) throws Exception;
 

/***
 * Adds interest in a NATS subject, with a custom handle.
 * @param subject - subject of interest.
 * @param handler - message handler
 * @throws Exception - an error occurred in the subsciption process.
 */
public void subscribe(String subject, MessageHandler handler) throws Exception;
 

/***
 * Adds interest in a NATS subject with a queue group, with a custom handler.
 * @param subject - subject of interest.
 * @param queue - work queue
 * @param handler - message handler
 * @throws Exception - an error occurred in the subsciption process.
 */
public void subscribe(String subject, String queue, MessageHandler handler) throws Exception;