Improve logging of failed connection attempts

also improve XMPPTCPConnection.connectUsingConfiguration(): Try further
hostAddresses if getAllByName failes.

Fixes SMACK-711

smack-core/src/main/java/org/jivesoftware/smack/util/dns/HostAddress.java

@@ -16,13 +16,20 @@
  */
 package org.jivesoftware.smack.util.dns;
 
+import java.net.InetAddress;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
 import org.jivesoftware.smack.SmackException.ConnectionException;
 import org.jivesoftware.smack.util.Objects;
 
 public class HostAddress {
     private final String fqdn;
     private final int port;
-    private Exception exception;
+    private final Map<InetAddress, Exception> exceptions = new LinkedHashMap<>();
 
     /**
      * Creates a new HostAddress with the given FQDN. The port will be set to the default XMPP client port: 5222
@@ -64,8 +71,13 @@ public class HostAddress {
         return port;
     }
 
-    public void setException(Exception e) {
+    public void setException(Exception exception) {
-        this.exception = e;
+        setException(null, exception);
+    }
+
+    public void setException(InetAddress inetAddress, Exception exception) {
+        Exception old = exceptions.put(inetAddress, exception);
+        assert(old == null);
     }
 
     /**
@@ -75,8 +87,8 @@ public class HostAddress {
      * 
      * @return the Exception causing this HostAddress to fail
      */
-    public Exception getException() {
+    public Map<InetAddress, Exception> getExceptions() {
-        return this.exception;
+        return Collections.unmodifiableMap(exceptions);
     }
 
     @Override
@@ -109,9 +121,24 @@ public class HostAddress {
     }
 
     public String getErrorMessage() {
-        if (exception == null) {
+        if (exceptions.isEmpty()) {
             return "No error logged";
         }
-        return "'" + toString() + "' failed because " + exception.toString();
+        StringBuilder sb = new StringBuilder();
+        sb.append('\'').append(toString()).append("' failed because: ");
+        Iterator<Entry<InetAddress, Exception>> iterator = exceptions.entrySet().iterator();
+        while (iterator.hasNext()) {
+            Entry<InetAddress, Exception> entry = iterator.next();
+            InetAddress inetAddress = entry.getKey();
+            if (inetAddress != null) {
+                sb.append(entry.getKey()).append(" exception: ");
+            }
+            sb.append(entry.getValue());
+            if (iterator.hasNext()) {
+                sb.append(", ");
+            }
+        }
+
+        return sb.toString();
     }
 }

smack-core/src/test/java/org/jivesoftware/smack/SmackExceptionTest.java

@@ -41,7 +41,7 @@ public class SmackExceptionTest {
 
         ConnectionException connectionException = ConnectionException.from(failedAddresses);
         String message = connectionException.getMessage();
-        assertEquals("The following addresses failed: 'foo.bar.example:1234' failed because java.lang.Exception: Failed for some reason, 'barz.example:5678' failed because java.lang.Exception: Failed for some other reason",
+        assertEquals("The following addresses failed: 'foo.bar.example:1234' failed because: java.lang.Exception: Failed for some reason, 'barz.example:5678' failed because: java.lang.Exception: Failed for some other reason",
                         message);
     }
 

smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java

@@ -119,6 +119,7 @@ import java.security.cert.CertificateException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
@@ -536,7 +537,7 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
         }
     }
 
-    private void connectUsingConfiguration() throws IOException, ConnectionException {
+    private void connectUsingConfiguration() throws ConnectionException, IOException {
         List<HostAddress> failedAddresses = populateHostAddresses();
         SocketFactory socketFactory = config.getSocketFactory();
         ProxyInfo proxyInfo = config.getProxyInfo();
@@ -545,16 +546,25 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
             socketFactory = SocketFactory.getDefault();
         }
         for (HostAddress hostAddress : hostAddresses) {
+            Iterator<InetAddress> inetAddresses = null;
             String host = hostAddress.getFQDN();
             int port = hostAddress.getPort();
             socket = socketFactory.createSocket();
             try {
-                Iterator<InetAddress> inetAddresses = Arrays.asList(InetAddress.getAllByName(host)).iterator();
+                inetAddresses = Arrays.asList(InetAddress.getAllByName(host)).iterator();
                 if (!inetAddresses.hasNext()) {
                     // This should not happen
                     LOGGER.warning("InetAddress.getAllByName() returned empty result array.");
                     throw new UnknownHostException(host);
                 }
+            }
+            catch (UnknownHostException e) {
+                hostAddress.setException(e);
+                // TODO: Change to emptyIterator() once Smack's minimum Android SDK level is >= 19.
+                List<InetAddress> emptyInetAddresses = Collections.emptyList();
+                inetAddresses = emptyInetAddresses.iterator();
+                continue;
+            }
             innerloop: while (inetAddresses.hasNext()) {
                 final InetAddress inetAddress = inetAddresses.next();
                 final String inetAddressAndPort = inetAddress + " at port " + port;
@@ -567,10 +577,12 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
                         proxyInfo.getProxySocketConnection().connect(socket, inetAddress, port, timeout);
                     }
                 } catch (Exception e) {
+                    hostAddress.setException(inetAddress, e);
                     if (inetAddresses.hasNext()) {
                         continue innerloop;
-                        } else {
+                    }
-                            throw e;
+                    else {
+                        break innerloop;
                     }
                 }
                 LOGGER.finer("Established TCP connection to " + inetAddressAndPort);
@@ -579,12 +591,8 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
                 this.port = port;
                 return;
             }
-            }
-            catch (Exception e) {
-                hostAddress.setException(e);
             failedAddresses.add(hostAddress);
         }
-        }
         // There are no more host addresses to try
         // throw an exception and report all tried
         // HostAddresses in the exception