OF-115 Process S2S stanzas from a session serially

This patch removes the thread pool from the ServerSocketReader, causing
stanzas from a particular S2S session to be processed serially on the same
thread used by the ServerSocketReader.

Each ServerSocketReader currently has a thread to itself, so this is unlikely
to have a serious impact on performance, but does have a very positive impact
on correctness.

src/java/org/jivesoftware/openfire/net/ServerSocketReader.java

@@ -61,23 +61,9 @@ public class ServerSocketReader extends SocketReader {
 
 	private static final Logger Log = LoggerFactory.getLogger(ServerSocketReader.class);
 
-    /**
-     * Pool of threads that are available for processing the requests.
-     */
-    private ThreadPoolExecutor threadPool;
-
     public ServerSocketReader(PacketRouter router, RoutingTable routingTable, String serverName,
             Socket socket, SocketConnection connection, boolean useBlockingMode) {
         super(router, routingTable, serverName, socket, connection, useBlockingMode);
-        // Create a pool of threads that will process received packets. If more threads are
-        // required then the command will be executed on the SocketReader process
-        int coreThreads = JiveGlobals.getIntProperty("xmpp.server.processing.core.threads", 2);
-        int maxThreads = JiveGlobals.getIntProperty("xmpp.server.processing.max.threads", 50);
-        int queueSize = JiveGlobals.getIntProperty("xmpp.server.processing.queue", 50);
-        threadPool =
-                new ThreadPoolExecutor(coreThreads, maxThreads, 60, TimeUnit.SECONDS,
-                        new LinkedBlockingQueue<Runnable>(queueSize),
-                        new ThreadPoolExecutor.CallerRunsPolicy());
     }
 
     /**
@@ -89,18 +75,12 @@ public class ServerSocketReader extends SocketReader {
 	protected void processIQ(final IQ packet) throws UnauthorizedException {
         try {
             packetReceived(packet);
-            // Process the packet in another thread
-            threadPool.execute(new Runnable() {
-                @Override
-                public void run() {
-                    try {
-                        ServerSocketReader.super.processIQ(packet);
-                    }
-                    catch (UnauthorizedException e) {
-                        Log.error("Error processing packet", e);
-                    }
-                }
-            });
+            try {
+                super.processIQ(packet);
+            }
+            catch (UnauthorizedException e) {
+                Log.error("Error processing packet", e);
+            }
         }
         catch (PacketRejectedException e) {
             Log.debug("IQ rejected: " + packet.toXML(), e);
@@ -116,18 +96,12 @@ public class ServerSocketReader extends SocketReader {
 	protected void processPresence(final Presence packet) throws UnauthorizedException {
         try {
             packetReceived(packet);
-            // Process the packet in another thread
-            threadPool.execute(new Runnable() {
-                @Override
-                public void run() {
-                    try {
-                        ServerSocketReader.super.processPresence(packet);
-                    }
-                    catch (UnauthorizedException e) {
-                        Log.error("Error processing packet", e);
-                    }
-                }
-            });
+            try {
+                super.processPresence(packet);
+            }
+            catch (UnauthorizedException e) {
+                Log.error("Error processing packet", e);
+            }
         }
         catch (PacketRejectedException e) {
             Log.debug("Presence rejected: " + packet.toXML(), e);
@@ -143,18 +117,12 @@ public class ServerSocketReader extends SocketReader {
 	protected void processMessage(final Message packet) throws UnauthorizedException {
         try {
             packetReceived(packet);
-            // Process the packet in another thread
-            threadPool.execute(new Runnable() {
-                @Override
-                public void run() {
-                    try {
-                        ServerSocketReader.super.processMessage(packet);
-                    }
-                    catch (UnauthorizedException e) {
-                        Log.error("Error processing packet", e);
-                    }
-                }
-            });
+            try {
+                ServerSocketReader.super.processMessage(packet);
+            }
+            catch (UnauthorizedException e) {
+                Log.error("Error processing packet", e);
+            }
         }
         catch (PacketRejectedException e) {
             Log.debug("Message rejected: " + packet.toXML(), e);
@@ -223,9 +191,6 @@ public class ServerSocketReader extends SocketReader {
     @Override
 	protected void shutdown() {
         super.shutdown();
-        // Shutdown the pool of threads that are processing packets sent by
-        // the remote server
-        threadPool.shutdown();
     }
 
     @Override