Convert Connection references to weak references

If a Manager is strong referenced from a gc root, usually the instances
map, it should not hold itself a strong reference the connection in
order to avoid a cycle that prevents the Connection instance from being
gc'ed.

SMACK-383

experimental/source/org/jivesoftware/smackx/carbons/CarbonManager.java

@@ -16,6 +16,7 @@
 
 package org.jivesoftware.smackx.carbons;
 
+import java.lang.ref.WeakReference;
 import java.util.Collections;
 import java.util.Map;
 import java.util.WeakHashMap;
@@ -56,13 +57,13 @@ public class CarbonManager {
         });
     }
     
-    private Connection connection;
+    private WeakReference<Connection> weakRefConnection;
     private volatile boolean enabled_state = false;
 
     private CarbonManager(Connection connection) {
         ServiceDiscoveryManager sdm = ServiceDiscoveryManager.getInstanceFor(connection);
         sdm.addFeature(Carbon.NAMESPACE);
-        this.connection = connection;
+        weakRefConnection = new WeakReference<Connection>(connection);
         instances.put(connection, this);
     }
 
@@ -99,6 +100,7 @@ public class CarbonManager {
      * @return true if supported
      */
     public boolean isSupportedByServer() {
+        Connection connection = weakRefConnection.get();
         try {
             DiscoverInfo result = ServiceDiscoveryManager
                 .getInstanceFor(connection).discoverInfo(connection.getServiceName());
@@ -118,6 +120,7 @@ public class CarbonManager {
      * @param new_state whether carbons should be enabled or disabled
      */
     public void sendCarbonsEnabled(final boolean new_state) {
+        final Connection connection = weakRefConnection.get();
         IQ setIQ = carbonsEnabledIQ(new_state);
 
         connection.addPacketListener(new PacketListener() {
@@ -148,6 +151,7 @@ public class CarbonManager {
         if (enabled_state == new_state)
             return true;
 
+        Connection connection = weakRefConnection.get();
         IQ setIQ = carbonsEnabledIQ(new_state);
 
         PacketCollector collector =

source/org/jivesoftware/smack/keepalive/KeepAliveManager.java

@@ -16,12 +16,12 @@
 
 package org.jivesoftware.smack.keepalive;
 
+import java.lang.ref.WeakReference;
 import java.util.Collections;
-import java.util.Date;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
+import java.util.WeakHashMap;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
@@ -52,7 +52,7 @@ import org.jivesoftware.smack.ping.packet.Ping;
  * @author Florian Schmaus
  */
 public class KeepAliveManager {
-    private static Map<Connection, KeepAliveManager> instances = new HashMap<Connection, KeepAliveManager>();
+    private static Map<Connection, KeepAliveManager> instances = Collections.synchronizedMap(new WeakHashMap<Connection, KeepAliveManager>());
     private static volatile ScheduledExecutorService periodicPingExecutorService;
     
     static {
@@ -65,7 +65,7 @@ public class KeepAliveManager {
         }
     }
 
-    private Connection connection;
+    private WeakReference<Connection> weakRefConnection;
     private long pingInterval = SmackConfiguration.getKeepAliveInterval();
     private Set<PingFailedListener> pingFailedListeners = Collections.synchronizedSet(new HashSet<PingFailedListener>());
     private volatile ScheduledFuture<?> periodicPingTask;
@@ -120,40 +120,21 @@ public class KeepAliveManager {
     }
     
     private KeepAliveManager(Connection connection) {
-        this.connection = connection;
+        weakRefConnection = new WeakReference<Connection>(connection);
-        init();
-        handleConnect();
-    }
 
-    /*
-     * Call after every connection to add the packet listener.
-     */
-    private void handleConnect() {
-        // Listen for all incoming packets and reset the scheduled ping whenever
-        // one arrives.
-        connection.addPacketListener(new PacketListener() {
-
-            @Override
-            public void processPacket(Packet packet) {
-                // reschedule the ping based on this last server contact
-                lastSuccessfulContact = System.currentTimeMillis();
-                schedulePingServerTask();
-            }
-        }, null);
-    }
-
-    private void init() {
         connection.addConnectionListener(new ConnectionListener() {
 
             @Override
             public void connectionClosed() {
                 stopPingServerTask();
+                Connection connection = weakRefConnection.get();
                 handleDisconnect(connection);
             }
 
             @Override
             public void connectionClosedOnError(Exception arg0) {
                 stopPingServerTask();
+                Connection connection = weakRefConnection.get();
                 handleDisconnect(connection);
             }
 
@@ -174,6 +155,25 @@ public class KeepAliveManager {
 
         instances.put(connection, this);
         schedulePingServerTask();
+        handleConnect();
+    }
+
+    /*
+     * Call after every connection to add the packet listener.
+     */
+    private void handleConnect() {
+        Connection connection = weakRefConnection.get();
+        // Listen for all incoming packets and reset the scheduled ping whenever
+        // one arrives.
+        connection.addPacketListener(new PacketListener() {
+
+            @Override
+            public void processPacket(Packet packet) {
+                // reschedule the ping based on this last server contact
+                lastSuccessfulContact = System.currentTimeMillis();
+                schedulePingServerTask();
+            }
+        }, null);
     }
 
     /**
@@ -276,6 +276,7 @@ public class KeepAliveManager {
                 public void run() {
                     Ping ping = new Ping();
                     PacketFilter responseFilter = new PacketIDFilter(ping.getPacketID());
+                    Connection connection = weakRefConnection.get();
                     final PacketCollector response = pingFailedListeners.isEmpty() ? null : connection.createPacketCollector(responseFilter);
                     connection.sendPacket(ping);
         

source/org/jivesoftware/smackx/MessageEventManager.java

@@ -20,7 +20,6 @@
 
 package org.jivesoftware.smackx;
 
-import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Iterator;

source/org/jivesoftware/smackx/ping/PingManager.java

@@ -16,6 +16,7 @@
 
 package org.jivesoftware.smackx.ping;
 
+import java.lang.ref.WeakReference;
 import java.util.Collections;
 import java.util.Map;
 import java.util.WeakHashMap;
@@ -65,7 +66,7 @@ public class PingManager {
         });
     }
 
-    private Connection connection;
+    private WeakReference<Connection> weakRefConnection;
 
     /**
      * Retrieves a {@link PingManager} for the specified {@link Connection}, creating one if it doesn't already
@@ -84,8 +85,8 @@ public class PingManager {
         return pingManager;
     }
 
-    private PingManager(Connection con) {
+    private PingManager(Connection connection) {
-        this.connection = con;
+        weakRefConnection = new WeakReference<Connection>(connection);
         ServiceDiscoveryManager sdm = ServiceDiscoveryManager.getInstanceFor(connection);
         
         // The ServiceDiscoveryManager was not pre-initialized
@@ -101,6 +102,7 @@ public class PingManager {
              * Sends a Pong for every Ping
              */
             public void processPacket(Packet packet) {
+                Connection connection = weakRefConnection.get();
                 IQ pong = IQ.createResultIQ((Ping) packet);
                 connection.sendPacket(pong);
             }
@@ -121,7 +123,7 @@ public class PingManager {
      */
     public boolean ping(String jid, long pingTimeout) {
         Ping ping = new Ping(jid);
-        
+        Connection connection = weakRefConnection.get();
         try {
             SyncPacketSend.getReply(connection, ping);
         }
@@ -151,6 +153,7 @@ public class PingManager {
      * @throws XMPPException An XMPP related error occurred during the request 
      */
     public boolean isPingSupported(String jid) throws XMPPException {
+        Connection connection = weakRefConnection.get();
         DiscoverInfo result = ServiceDiscoveryManager.getInstanceFor(connection).discoverInfo(jid);
         return result.containsFeature(Ping.NAMESPACE);
     }
@@ -165,6 +168,7 @@ public class PingManager {
      * @return true if a reply was received from the server, false otherwise.
      */
     public boolean pingMyServer() {
+        Connection connection = weakRefConnection.get();
         return ping(connection.getServiceName());
     }
 }

source/org/jivesoftware/smackx/receipts/DeliveryReceiptManager.java

@@ -16,6 +16,7 @@
 
 package org.jivesoftware.smackx.receipts;
 
+import java.lang.ref.WeakReference;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Map;
@@ -52,7 +53,7 @@ public class DeliveryReceiptManager implements PacketListener {
         });
     }
 
-    private Connection connection;
+    private WeakReference<Connection> weakRefConnection;
     private boolean auto_receipts_enabled = false;
     private Set<ReceiptReceivedListener> receiptReceivedListeners = Collections
             .synchronizedSet(new HashSet<ReceiptReceivedListener>());
@@ -60,7 +61,7 @@ public class DeliveryReceiptManager implements PacketListener {
     private DeliveryReceiptManager(Connection connection) {
         ServiceDiscoveryManager sdm = ServiceDiscoveryManager.getInstanceFor(connection);
         sdm.addFeature(DeliveryReceipt.NAMESPACE);
-        this.connection = connection;
+        weakRefConnection = new WeakReference<Connection>(connection);
         instances.put(connection, this);
 
         // register listener for delivery receipts and requests
@@ -91,6 +92,7 @@ public class DeliveryReceiptManager implements PacketListener {
      * @return true if supported
      */
     public boolean isSupported(String jid) {
+        Connection connection = weakRefConnection.get();
         try {
             DiscoverInfo result =
                 ServiceDiscoveryManager.getInstanceFor(connection).discoverInfo(jid);
@@ -119,6 +121,7 @@ public class DeliveryReceiptManager implements PacketListener {
             DeliveryReceiptRequest drr = (DeliveryReceiptRequest)packet.getExtension(
                     DeliveryReceiptRequest.ELEMENT, DeliveryReceipt.NAMESPACE);
             if (drr != null) {
+                Connection connection = weakRefConnection.get();
                 Message ack = new Message(packet.getFrom(), Message.Type.normal);
                 ack.addExtension(new DeliveryReceipt(packet.getPacketID()));
                 connection.sendPacket(ack);