Throw NotConnectedException instead of NoResponseException

if the connection is not connected in sendStanzaWithResponseCallback and
in PacketCollector.

Also decrease log level if roster result listener's exeption callback is
invoked with a NotConnectedException.

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

@@ -1466,7 +1466,14 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
                 // If the packetListener got removed, then it was never run and
                 // we never received a response, inform the exception callback
                 if (removed && exceptionCallback != null) {
-                    exceptionCallback.processException(NoResponseException.newWith(AbstractXMPPConnection.this, replyFilter));
+                    Exception exception;
+                    if (!isConnected()) {
+                        // If the connection is no longer connected, throw a not connected exception.
+                        exception = new NotConnectedException(AbstractXMPPConnection.this, replyFilter);
+                    } else {
+                        exception = NoResponseException.newWith(AbstractXMPPConnection.this, replyFilter);
+                    }
+                    exceptionCallback.processException(exception);
                 }
             }
         }, timeout, TimeUnit.MILLISECONDS);

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

@@ -20,6 +20,7 @@ package org.jivesoftware.smack;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.TimeUnit;
 
+import org.jivesoftware.smack.SmackException.NotConnectedException;
 import org.jivesoftware.smack.SmackException.NoResponseException;
 import org.jivesoftware.smack.XMPPException.XMPPErrorException;
 import org.jivesoftware.smack.filter.StanzaFilter;
@@ -199,8 +200,10 @@ public class PacketCollector {
      * @throws XMPPErrorException in case an error response.
      * @throws NoResponseException if there was no response from the server.
      * @throws InterruptedException 
+     * @throws NotConnectedException 
      */
-    public <P extends Stanza> P nextResultOrThrow() throws NoResponseException, XMPPErrorException, InterruptedException {
+    public <P extends Stanza> P nextResultOrThrow() throws NoResponseException, XMPPErrorException,
+                    InterruptedException, NotConnectedException {
         return nextResultOrThrow(connection.getPacketReplyTimeout());
     }
 
@@ -213,11 +216,16 @@ public class PacketCollector {
      * @throws NoResponseException if there was no response from the server.
      * @throws XMPPErrorException in case an error response.
      * @throws InterruptedException 
+     * @throws NotConnectedException 
      */
-    public <P extends Stanza> P nextResultOrThrow(long timeout) throws NoResponseException, XMPPErrorException, InterruptedException {
+    public <P extends Stanza> P nextResultOrThrow(long timeout) throws NoResponseException,
+                    XMPPErrorException, InterruptedException, NotConnectedException {
         P result = nextResult(timeout);
         cancel();
         if (result == null) {
+            if (!connection.isConnected()) {
+                throw new NotConnectedException(connection, packetFilter);
+            }
             throw NoResponseException.newWith(connection, this);
         }
 

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

@@ -171,6 +171,11 @@ public class SmackException extends Exception {
             super("The connection " + connection.toString() + " is no longer connected. "
                             + details);
         }
+
+        public NotConnectedException(XMPPConnection connection, StanzaFilter stanzaFilter) {
+            super("The connection " + connection
+                            + " is no longer connected while waiting for response with " + stanzaFilter);
+        }
     }
 
     public static class IllegalStateChangeException extends SmackException {

smack-im/src/main/java/org/jivesoftware/smack/roster/Roster.java

@@ -341,7 +341,13 @@ public final class Roster extends Manager {
         connection.sendIqWithResponseCallback(packet, new RosterResultListener(), new ExceptionCallback() {
             @Override
             public void processException(Exception exception) {
-                LOGGER.log(Level.SEVERE, "Exception reloading roster" , exception);
+                Level logLevel;
+                if (exception instanceof NotConnectedException) {
+                    logLevel = Level.FINE;
+                } else {
+                    logLevel = Level.SEVERE;
+                }
+                LOGGER.log(logLevel, "Exception reloading roster" , exception);
             }
         });
     }