Re-enable DNS round robin

src/main/java/com/rabbitmq/client/Address.java

@@ -16,6 +16,7 @@
 
 package com.rabbitmq.client;
 
+import java.net.InetSocketAddress;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -161,6 +162,13 @@ public static Address parseAddress(String addressString) {
         }
     }
 
+    /**
+     * Construct an InetSocketAddress for this address with a specific port
+     */
+    public InetSocketAddress toInetSocketAddress(int port) {
+        return new InetSocketAddress(getHost(), port);
+    }
+
     /**
      * Array-based factory method: takes an array of formatted address strings as construction parameter
      * @param addresses array of strings of form "host[:port],..."
@@ -191,5 +199,4 @@ public static Address[] parseAddresses(String addresses) {
     @Override public String toString() {
         return _port == -1 ? _host : _host + ":" + _port;
     }
-
 }

src/main/java/com/rabbitmq/client/ConnectionFactory.java

@@ -1339,7 +1339,11 @@ public Connection newConnection(ExecutorService executor, String connectionName)
     }
 
     protected AddressResolver createAddressResolver(List<Address> addresses) {
-        return new ListAddressResolver(addresses);
+        if (addresses.size() > 1) {
+            return new ListAddressResolver(addresses);
+        } else {
+            return new DnsRecordIpAddressResolver(addresses.get(0), isSSL());
+        }
     }
 
     @Override public ConnectionFactory clone(){

src/main/java/com/rabbitmq/client/DnsRecordIpAddressResolver.java

@@ -72,9 +72,9 @@ public List<Address> getAddresses() throws UnknownHostException {
 
         InetAddress[] inetAddresses = resolveIpAddresses(hostName);
 
-        List<Address> addresses = new ArrayList<Address>();
+        List<Address> addresses = new ArrayList<>();
         for (InetAddress inetAddress : inetAddresses) {
-            addresses.add(new Address(inetAddress.getHostAddress(), portNumber));
+            addresses.add(new ResolvedInetAddress(hostName, inetAddress, portNumber));
         }
         return addresses;
     }

src/main/java/com/rabbitmq/client/ResolvedInetAddress.java

@@ -0,0 +1,18 @@
+package com.rabbitmq.client;
+
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+
+public class ResolvedInetAddress extends Address {
+    private final InetAddress inetAddress;
+
+    public ResolvedInetAddress(String originalHostname, InetAddress inetAddress, int port) {
+        super(originalHostname, port);
+        this.inetAddress = inetAddress;
+    }
+
+    @Override
+    public InetSocketAddress toInetSocketAddress(int port) {
+        return new InetSocketAddress(inetAddress, port);
+    }
+}

src/main/java/com/rabbitmq/client/impl/SocketFrameHandlerFactory.java

@@ -22,7 +22,6 @@
 
 import javax.net.SocketFactory;
 import java.io.IOException;
-import java.net.InetSocketAddress;
 import java.net.Socket;
 import java.util.concurrent.ExecutorService;
 
@@ -51,14 +50,13 @@ public SocketFrameHandlerFactory(int connectionTimeout, SocketFactory socketFact
     }
 
     public FrameHandler create(Address addr, String connectionName) throws IOException {
-        String hostName = addr.getHost();
         int portNumber = ConnectionFactory.portOrDefault(addr.getPort(), ssl);
         Socket socket = null;
         try {
             socket = createSocket(connectionName);
             configurator.configure(socket);
-            socket.connect(new InetSocketAddress(hostName, portNumber),
-                    connectionTimeout);
+
+            socket.connect(addr.toInetSocketAddress(portNumber), connectionTimeout);
             return create(socket);
         } catch (IOException ioe) {
             quietTrySocketClose(socket);

src/main/java/com/rabbitmq/client/impl/nio/SocketChannelFrameHandlerFactory.java

@@ -85,7 +85,7 @@ public FrameHandler create(Address addr, String connectionName) throws IOExcepti
                 }
             }
 
-            SocketAddress address = new InetSocketAddress(addr.getHost(), portNumber);
+            SocketAddress address = addr.toInetSocketAddress(portNumber);
             // No Sonar: the channel is closed in case of error and it cannot
             // be closed here because it's part of the state of the connection
             // to be returned.

src/test/java/com/rabbitmq/client/test/ConnectionFactoryTest.java

@@ -96,7 +96,7 @@ protected synchronized FrameHandlerFactory createFrameHandlerFactory() {
     }
 
     @Test
-    public void shouldNotUseDnsResolutionWhenOneAddressAndNoTls() throws Exception {
+    public void shouldUseDnsResolutionWhenOneAddressAndNoTls() throws Exception {
         AMQConnection connection = mock(AMQConnection.class);
         AtomicReference<AddressResolver> addressResolver = new AtomicReference<>();
 
@@ -123,11 +123,11 @@ protected synchronized FrameHandlerFactory createFrameHandlerFactory() {
 
         doNothing().when(connection).start();
         connectionFactory.newConnection();
-        assertThat(addressResolver.get()).isNotNull().isInstanceOf(ListAddressResolver.class);
+        assertThat(addressResolver.get()).isNotNull().isInstanceOf(DnsRecordIpAddressResolver.class);
     }
 
     @Test
-    public void shouldNotUseDnsResolutionWhenOneAddressAndTls() throws Exception {
+    public void shouldUseDnsResolutionWhenOneAddressAndTls() throws Exception {
         AMQConnection connection = mock(AMQConnection.class);
         AtomicReference<AddressResolver> addressResolver = new AtomicReference<>();
 
@@ -156,7 +156,7 @@ protected synchronized FrameHandlerFactory createFrameHandlerFactory() {
         connectionFactory.useSslProtocol();
         connectionFactory.newConnection();
 
-        assertThat(addressResolver.get()).isNotNull().isInstanceOf(ListAddressResolver.class);
+        assertThat(addressResolver.get()).isNotNull().isInstanceOf(DnsRecordIpAddressResolver.class);
     }
 
     @Test