Examples with Poller org.zeromq.ZMQ.Poller used on opensource projects

Example 1 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class bstarcli method main.

public static void main(String[] argv) throws Exception {
    ZContext ctx = new ZContext();
    String[] server = { "tcp://localhost:5001", "tcp://localhost:5002" };
    int serverNbr = 0;
    System.out.printf("I: connecting to server at %s...\n", server[serverNbr]);
    Socket client = ctx.createSocket(ZMQ.REQ);
    client.connect(server[serverNbr]);
    Poller poller = ctx.createPoller(1);
    poller.register(client, ZMQ.Poller.POLLIN);
    int sequence = 0;
    while (!Thread.currentThread().isInterrupted()) {
        //  We send a request, then we work to get a reply
        String request = String.format("%d", ++sequence);
        client.send(request);
        boolean expectReply = true;
        while (expectReply) {
            //  Poll socket for a reply, with timeout
            int rc = poller.poll(REQUEST_TIMEOUT);
            if (rc == -1)
                //  Interrupted
                break;
            if (poller.pollin(0)) {
                //  We got a reply from the server, must match getSequence
                String reply = client.recvStr();
                if (Integer.parseInt(reply) == sequence) {
                    System.out.printf("I: server replied OK (%s)\n", reply);
                    expectReply = false;
                    //  One request per second
                    Thread.sleep(1000);
                } else
                    System.out.printf("E: bad reply from server: %s\n", reply);
            } else {
                System.out.printf("W: no response from server, failing over\n");
                //  Old socket is confused; close it and open a new one
                poller.unregister(client);
                ctx.destroySocket(client);
                serverNbr = (serverNbr + 1) % 2;
                Thread.sleep(SETTLE_DELAY);
                System.out.printf("I: connecting to server at %s...\n", server[serverNbr]);
                client = ctx.createSocket(ZMQ.REQ);
                client.connect(server[serverNbr]);
                poller.register(client, ZMQ.Poller.POLLIN);
                //  Send request again, on new socket
                client.send(request);
            }
        }
    }
    ctx.destroy();
}

Example 2 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class lbbroker2 method main.

/**
     * This is the main task. This has the identical functionality to
     * the previous lbbroker example but uses higher level classes to start child threads
     * to hold the list of workers, and to read and send messages:
     */
public static void main(String[] args) {
    ZContext context = new ZContext();
    //  Prepare our context and sockets
    Socket frontend = context.createSocket(ZMQ.ROUTER);
    Socket backend = context.createSocket(ZMQ.ROUTER);
    frontend.bind("ipc://frontend.ipc");
    backend.bind("ipc://backend.ipc");
    int clientNbr;
    for (clientNbr = 0; clientNbr < NBR_CLIENTS; clientNbr++) ZThread.start(new ClientTask());
    for (int workerNbr = 0; workerNbr < NBR_WORKERS; workerNbr++) ZThread.start(new WorkerTask());
    //  Queue of available workers
    Queue<ZFrame> workerQueue = new LinkedList<ZFrame>();
    while (!Thread.currentThread().isInterrupted()) {
        //  Initialize poll set
        Poller items = context.createPoller(2);
        //  Always poll for worker activity on backend
        items.register(backend, Poller.POLLIN);
        //  Poll front-end only if we have available workers
        if (workerQueue.size() > 0)
            items.register(frontend, Poller.POLLIN);
        if (items.poll() < 0)
            //  Interrupted
            break;
        //  Handle worker activity on backend
        if (items.pollin(0)) {
            ZMsg msg = ZMsg.recvMsg(backend);
            if (msg == null)
                //  Interrupted
                break;
            ZFrame identity = msg.unwrap();
            //  Queue worker address for LRU routing
            workerQueue.add(identity);
            //  Forward message to client if it's not a READY
            ZFrame frame = msg.getFirst();
            if (Arrays.equals(frame.getData(), WORKER_READY))
                msg.destroy();
            else
                msg.send(frontend);
        }
        if (items.pollin(1)) {
            //  Get client request, route to first available worker
            ZMsg msg = ZMsg.recvMsg(frontend);
            if (msg != null) {
                msg.wrap(workerQueue.poll());
                msg.send(backend);
            }
        }
    }
    context.destroy();
}

Example 3 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class lpclient method main.

public static void main(String[] argv) {
    ZContext ctx = new ZContext();
    System.out.println("I: connecting to server");
    Socket client = ctx.createSocket(ZMQ.REQ);
    assert (client != null);
    client.connect(SERVER_ENDPOINT);
    Poller poller = ctx.createPoller(1);
    poller.register(client, Poller.POLLIN);
    int sequence = 0;
    int retriesLeft = REQUEST_RETRIES;
    while (retriesLeft > 0 && !Thread.currentThread().isInterrupted()) {
        //  We send a request, then we work to get a reply
        String request = String.format("%d", ++sequence);
        client.send(request);
        int expect_reply = 1;
        while (expect_reply > 0) {
            //  Poll socket for a reply, with timeout
            int rc = poller.poll(REQUEST_TIMEOUT);
            if (rc == -1)
                //  Interrupted
                break;
            if (poller.pollin(0)) {
                //  We got a reply from the server, must match getSequence
                String reply = client.recvStr();
                if (reply == null)
                    //  Interrupted
                    break;
                if (Integer.parseInt(reply) == sequence) {
                    System.out.printf("I: server replied OK (%s)\n", reply);
                    retriesLeft = REQUEST_RETRIES;
                    expect_reply = 0;
                } else
                    System.out.printf("E: malformed reply from server: %s\n", reply);
            } else if (--retriesLeft == 0) {
                System.out.println("E: server seems to be offline, abandoning\n");
                break;
            } else {
                System.out.println("W: no response from server, retrying\n");
                //  Old socket is confused; close it and open a new one
                poller.unregister(client);
                ctx.destroySocket(client);
                System.out.println("I: reconnecting to server\n");
                client = ctx.createSocket(ZMQ.REQ);
                client.connect(SERVER_ENDPOINT);
                poller.register(client, Poller.POLLIN);
                //  Send request again, on new socket
                client.send(request);
            }
        }
    }
    ctx.destroy();
}

Example 4 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class lvcache method main.

public static void main(String[] args) {
    ZContext context = new ZContext();
    Socket frontend = context.createSocket(ZMQ.SUB);
    frontend.bind("tcp://*:5557");
    Socket backend = context.createSocket(ZMQ.XPUB);
    backend.bind("tcp://*:5558");
    //  Subscribe to every single topic from publisher
    frontend.subscribe(ZMQ.SUBSCRIPTION_ALL);
    //  Store last instance of each topic in a cache
    Map<String, String> cache = new HashMap<String, String>();
    Poller poller = context.createPoller(2);
    poller.register(frontend, Poller.POLLIN);
    poller.register(backend, Poller.POLLIN);
    //  if anything:
    while (true) {
        if (poller.poll(1000) == -1)
            //  Interrupted
            break;
        //  Any new topic data we cache and then forward
        if (poller.pollin(0)) {
            String topic = frontend.recvStr();
            String current = frontend.recvStr();
            if (topic == null)
                break;
            cache.put(topic, current);
            backend.sendMore(topic);
            backend.send(current);
        }
        //  When we get a new subscription, we pull data from the cache:
        if (poller.pollin(1)) {
            ZFrame frame = ZFrame.recvFrame(backend);
            if (frame == null)
                break;
            //  Event is one byte 0=unsub or 1=sub, followed by topic
            byte[] event = frame.getData();
            if (event[0] == 1) {
                String topic = new String(event, 1, event.length - 1, ZMQ.CHARSET);
                System.out.printf("Sending cached topic %s\n", topic);
                String previous = cache.get(topic);
                if (previous != null) {
                    backend.sendMore(topic);
                    backend.send(previous);
                }
            }
            frame.destroy();
        }
    }
    context.destroy();
}

Example 5 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class flclient2 method request.

private ZMsg request(ZMsg request) {
    //  Prefix request with getSequence number and empty envelope
    String sequenceText = String.format("%d", ++sequence);
    request.push(sequenceText);
    request.push("");
    //  Blast the request to all connected servers
    int server;
    for (server = 0; server < servers; server++) {
        ZMsg msg = request.duplicate();
        msg.send(socket);
    }
    //  Wait for a matching reply to arrive from anywhere
    //  Since we can poll several times, calculate each one
    ZMsg reply = null;
    long endtime = System.currentTimeMillis() + GLOBAL_TIMEOUT;
    Poller poller = ctx.createPoller(1);
    poller.register(socket, Poller.POLLIN);
    while (System.currentTimeMillis() < endtime) {
        poller.poll(endtime - System.currentTimeMillis());
        if (poller.pollin(0)) {
            //  Reply is [empty][getSequence][OK]
            reply = ZMsg.recvMsg(socket);
            assert (reply.size() == 3);
            reply.pop();
            String sequenceStr = reply.popString();
            int sequenceNbr = Integer.parseInt(sequenceStr);
            if (sequenceNbr == sequence)
                break;
            reply.destroy();
        }
    }
    request.destroy();
    return reply;
}