Add XMPPConnection.addAsyncPacketListener(PacketListener, PacketFilter)

and use this method in packet listeners that previously used Async.go().

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

@@ -131,6 +131,8 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
     private final Map<PacketListener, ListenerWrapper> recvListeners =
             new HashMap<PacketListener, ListenerWrapper>();
 
+    private final Map<PacketListener, ListenerWrapper> asyncRecvListeners = new HashMap<>();
+
     /**
      * List of PacketListeners that will be notified when a new packet was sent.
      */
@@ -741,6 +743,24 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
         }
     }
 
+    @Override
+    public void addAsyncPacketListener(PacketListener packetListener, PacketFilter packetFilter) {
+        if (packetListener == null) {
+            throw new NullPointerException("Packet listener is null.");
+        }
+        ListenerWrapper wrapper = new ListenerWrapper(packetListener, packetFilter);
+        synchronized (asyncRecvListeners) {
+            asyncRecvListeners.put(packetListener, wrapper);
+        }
+    }
+
+    @Override
+    public boolean removeAsyncPacketListener(PacketListener packetListener) {
+        synchronized (asyncRecvListeners) {
+            return asyncRecvListeners.remove(packetListener) != null;
+        }
+    }
+
     @Override
     public void addPacketSendingListener(PacketListener packetListener, PacketFilter packetFilter) {
         if (packetListener == null) {
@@ -937,14 +957,39 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
      *
      * @param packet the packet to notify the PacketCollectors and receive listeners about.
      */
-    protected void invokePacketCollectorsAndNotifyRecvListeners(Packet packet) {
+    protected void invokePacketCollectorsAndNotifyRecvListeners(final Packet packet) {
+        // First handle the async recv listeners. Note that this code is very similar to what follows a few lines below,
+        // the only difference is that asyncRecvListeners is used here and that the packet listeners are started in
+        // their own thread.
+        Collection<PacketListener> listenersToNotify = new LinkedList<PacketListener>();
+        synchronized (asyncRecvListeners) {
+            for (ListenerWrapper listenerWrapper : asyncRecvListeners.values()) {
+                if (listenerWrapper.filterMatches(packet)) {
+                    listenersToNotify.add(listenerWrapper.getListener());
+                }
+            }
+        }
+
+        for (final PacketListener listener : listenersToNotify) {
+            asyncGo(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        listener.processPacket(packet);
+                    } catch (Exception e) {
+                        LOGGER.log(Level.SEVERE, "Exception in async packet listener", e);
+                    }
+                }
+            });
+        }
+
         // Loop through all collectors and notify the appropriate ones.
         for (PacketCollector collector: collectors) {
             collector.processPacket(packet);
         }
 
         // Notify the receive listeners interested in the packet
-        List<PacketListener> listenersToNotify = new LinkedList<PacketListener>();
+        listenersToNotify = new LinkedList<PacketListener>();
         synchronized (recvListeners) {
             for (ListenerWrapper listenerWrapper : recvListeners.values()) {
                 if (listenerWrapper.filterMatches(packet)) {

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

@@ -266,6 +266,29 @@ public interface XMPPConnection {
      */
     public boolean removePacketListener(PacketListener packetListener);
 
+    /**
+     * Registers an <b>asynchronous</b> packet listener with this connection. A packet listener will be invoked only
+     * when an incoming packet is received. A packet filter determines which packets will be delivered to the listener.
+     * If the same packet listener is added again with a different filter, only the new filter will be used.
+     * <p>
+     * Unlike {@link #addPacketListener(PacketListener, PacketFilter)} packet listeners added with this method will be
+     * invoked asynchronously in their own thread. Use this method if the order of the packet listeners must not depend
+     * on the order how the stanzas where received.
+     * </p>
+     * 
+     * @param packetListener the packet listener to notify of new received packets.
+     * @param packetFilter the packet filter to use.
+     */
+    public void addAsyncPacketListener(PacketListener packetListener, PacketFilter packetFilter);
+
+    /**
+     * Removes an <b>asynchronous</b> packet listener for received packets from this connection.
+     * 
+     * @param packetListener the packet listener to remove.
+     * @return true if the packet listener was removed
+     */
+    public boolean removeAsyncPacketListener(PacketListener packetListener);
+
     /**
      * Registers a packet listener with this connection. The listener will be
      * notified of every packet that this connection sends. A packet filter determines