Usage of Listener on DNSResolver

DNSPromise.java

import java.net.InetSocketAddress;

import io.netty.channel.AddressedEnvelope;
import io.netty.handler.codec.dns.DnsRecord;
import io.netty.handler.codec.dns.DnsResponse;
import io.netty.handler.codec.dns.DnsSection;
import io.netty.util.concurrent.DefaultPromise;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.GenericFutureListener;

public class DnsPromise extends DefaultPromise<AddressedEnvelope<? extends DnsResponse,InetSocketAddress>>{
	
	public DnsPromise() {
		addListener(new DnsListener());
	}
	
	public class DnsListener implements GenericFutureListener<Future <AddressedEnvelope<? extends DnsResponse,InetSocketAddress>>>{

		@Override
		public void operationComplete(Future<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>> future)
				throws Exception {
			DnsResponse response = future.getNow().content();
			DnsRecord answer = response.recordAt(DnsSection.ANSWER);
			if (answer != null) {
				System.out.println("POSITIVE ANSWER "+ answer.name()+ " TTL "+ answer.timeToLive());
			}else {
				DnsRecord authoritity = response.recordAt(DnsSection.AUTHORITY);
				System.out.println("Negative ANSWER TTL" + authoritity.timeToLive());
				
			}
			
			
		}

		
	}
}

MainClass.java

import java.net.InetSocketAddress;
import java.util.concurrent.ExecutionException;

import io.netty.channel.AddressedEnvelope;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioDatagramChannel;
import io.netty.handler.codec.dns.DefaultDnsQuestion;
import io.netty.handler.codec.dns.DnsQuestion;
import io.netty.handler.codec.dns.DnsRecordType;
import io.netty.handler.codec.dns.DnsResponse;
import io.netty.resolver.dns.DnsNameResolver;
import io.netty.resolver.dns.DnsNameResolverBuilder;
import io.netty.resolver.dns.SingletonDnsServerAddressStreamProvider;
import io.netty.util.concurrent.Future;

public class MainClass {

	public static void main(String[] args) throws InterruptedException, ExecutionException {
	    EventLoopGroup group = new NioEventLoopGroup(1);    		
	    //DnsNameResolver dnsNameResolver = new DnsNameResolver(group.next(),NioDatagramChannel.class,DnsServerAddresses.shuffled(SERVERS)); 
	    DnsNameResolver dnsNameResolver = new DnsNameResolverBuilder(group.next())
	    		.channelType(NioDatagramChannel.class)
	    		.nameServerProvider(new SingletonDnsServerAddressStreamProvider(new InetSocketAddress("127.0.0.1", 53)))
	    		.build();
	    		int i = 154;
	    		int j = 6;
	    		String query = j+ "." + i + "." + "228.160.in-addr.arpa";
	    		DnsQuestion dnsQuestion = new DefaultDnsQuestion(query, DnsRecordType.PTR);
	    		Future<AddressedEnvelope<DnsResponse,InetSocketAddress>> futureResponse = dnsNameResolver.query(dnsQuestion,new DnsPromise());	    		
	    		System.out.println("apres");
	}
	

	

}