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package com.juick.components.s2s;

import org.apache.commons.lang3.math.NumberUtils;

import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Hashtable;
import java.util.Random;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.DirContext;
import javax.naming.directory.InitialDirContext;

/**
 *
 * @author ugnich
 */
public class DNSQueries {

    private static Random rand = new Random();

    public static InetSocketAddress getServerAddress(String hostname) throws UnknownHostException, NamingException {

        String host = hostname;
        int port = 5269;

        Hashtable<String, String> env = new Hashtable<>(5);
        env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
        DirContext ctx = new InitialDirContext(env);
        Attribute att = ctx.getAttributes("_xmpp-server._tcp." + hostname, new String[]{"SRV"}).get("SRV");

        if (att != null && att.size() > 0) {
            int i = rand.nextInt(att.size());
            String srv[] = att.get(i).toString().split(" ");
            port = NumberUtils.toInt(srv[2], 5269);
            host = srv[3];
        }
        ctx.close();
        return new InetSocketAddress(host, port);
    }
}