Add AbstractXMPPConnection.getUsedSaslMechanism()

and improve isAnonymous(). Also some minor changes to
SASLAuthentication.

smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java

@@ -73,6 +73,7 @@ import org.jivesoftware.smack.packet.XMPPError;
 import org.jivesoftware.smack.parsing.ParsingExceptionCallback;
 import org.jivesoftware.smack.provider.ExtensionElementProvider;
 import org.jivesoftware.smack.provider.ProviderManager;
+import org.jivesoftware.smack.sasl.core.SASLAnonymous;
 import org.jivesoftware.smack.util.DNSUtil;
 import org.jivesoftware.smack.util.Objects;
 import org.jivesoftware.smack.util.PacketParserUtils;
@@ -551,8 +552,19 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
 
     @Override
     public final boolean isAnonymous() {
-        return config.getUsername() == null && usedUsername == null
-                        && !config.allowNullOrEmptyUsername;
+        return isAuthenticated() && SASLAnonymous.NAME.equals(getUsedSaslMechansism());
+    }
+
+    /**
+     * Get the name of the SASL mechanism that was used to authenticate this connection. This returns the name of
+     * mechanism which was used the last time this conneciton was authenticated, and will return <code>null</code> if
+     * this connection was not authenticated before.
+     * 
+     * @return the name of the used SASL mechanism.
+     * @since 4.2
+     */
+    public final String getUsedSaslMechansism() {
+        return saslAuthentication.getNameOfLastUsedSaslMechansism();
     }
 
     private DomainBareJid xmppServiceDomain;

smack-core/src/main/java/org/jivesoftware/smack/SASLAuthentication.java

@@ -56,7 +56,7 @@ import java.util.logging.Logger;
  * @author Gaston Dombiak
  * @author Jay Kline
  */
-public class SASLAuthentication {
+public final class SASLAuthentication {
 
     private static final Logger LOGGER = Logger.getLogger(SASLAuthentication.class.getName());
 
@@ -294,11 +294,19 @@ public class SASLAuthentication {
      * is used by the connection at the first login and then reused after the connection
      * is disconnected and then reconnected.
      */
-    protected void init() {
+    void init() {
         authenticationSuccessful = false;
         saslException = null;
     }
 
+    String getNameOfLastUsedSaslMechansism() {
+        SASLMechanism lastUsedMech = currentMechanism;
+        if (lastUsedMech == null) {
+            return null;
+        }
+        return lastUsedMech.getName();
+    }
+
     private SASLMechanism selectMechanism() throws SmackException {
         Iterator<SASLMechanism> it = REGISTERED_MECHANISMS.iterator();
         final List<String> serverMechanisms = getServerMechanisms();