package guide;

import org.zeromq.SocketType;

import org.zeromq.ZContext;

import org.zeromq.ZMQ;

import org.zeromq.ZMQ.Poller;

import org.zeromq.ZMQ.Socket;

import org.zeromq.ZMsg;

// Freelance client - Model 1

// Uses REQ socket to query one or more services

public class flclient1

{

private static final int REQUEST_TIMEOUT = 1000;

private static final int MAX_RETRIES = 3; // Before we abandon

private static ZMsg tryRequest(ZContext ctx, String endpoint, ZMsg request)

{

System.out.printf("I: trying echo service at %s...\n", endpoint);

Socket client = ctx.createSocket(SocketType.REQ);

client.connect(endpoint);

// Send request, wait safely for reply

ZMsg msg = request.duplicate();

msg.send(client);

Poller poller = ctx.createPoller(1);

poller.register(client, Poller.POLLIN);

poller.poll(REQUEST_TIMEOUT);

ZMsg reply = null;

if (poller.pollin(0))

reply = ZMsg.recvMsg(client);

// Close socket in any case, we're done with it now

ctx.destroySocket(client);

poller.close();

return reply;

}

// .split client task

// The client uses a Lazy Pirate strategy if it only has one server to talk

// to. If it has two or more servers to talk to, it will try each server just

// once:

public static void main(String[] argv)

{

try (ZContext ctx = new ZContext()) {

ZMsg request = new ZMsg();

request.add("Hello world");

ZMsg reply = null;

int endpoints = argv.length;

if (endpoints == 0)

System.out.printf("I: syntax: flclient1 <endpoint> ...\n");

else if (endpoints == 1) {

// For one endpoint, we retry N times

int retries;

for (retries = 0; retries < MAX_RETRIES; retries++) {

String endpoint = argv[0];

reply = tryRequest(ctx, endpoint, request);

if (reply != null)

break; // Successful

System.out.printf(

"W: no response from %s, retrying...\n", endpoint

);

}

}

else {

// For multiple endpoints, try each at most once

int endpointNbr;

for (endpointNbr = 0; endpointNbr < endpoints; endpointNbr++) {

String endpoint = argv[endpointNbr];

reply = tryRequest(ctx, endpoint, request);

if (reply != null)

break; // Successful

System.out.printf("W: no response from %s\n", endpoint);

}

}

if (reply != null) {

System.out.printf("Service is running OK\n");

reply.destroy();

}

request.destroy();

}

}

}