Extracted the concept of a presence watcher from PresenceManager and defined an interface PresenceWatcher.

A concept of a Presence Watcher that is used to monitor the presence of
nicks on the network is defined. The basic polling mechanism for
watching nicks is extracted from the PresenceManager implementation and
is promoted to a new class which implements the PresenceWatcher
interface.

3 files changed, 620 insertions, 495 deletions

diff --git a/src/net/java/sip/communicator/impl/protocol/irc/BasicPollerPresenceWatcher.java b/src/net/java/sip/communicator/impl/protocol/irc/BasicPollerPresenceWatcher.java
new file mode 100644
index 0000000..10f1413
--- /dev/null
+++ b/src/net/java/sip/communicator/impl/protocol/irc/BasicPollerPresenceWatcher.java
@@ -0,0 +1,563 @@
+/*
+ * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.impl.protocol.irc;
+
+import java.util.*;
+import java.util.concurrent.atomic.*;
+
+import net.java.sip.communicator.util.*;
+
+import com.ircclouds.irc.api.*;
+import com.ircclouds.irc.api.domain.*;
+import com.ircclouds.irc.api.domain.messages.*;
+import com.ircclouds.irc.api.state.*;
+
+class BasicPollerPresenceWatcher
+    implements PresenceWatcher
+{
+    /**
+     * Logger.
+     */
+    private static final Logger LOGGER = Logger
+        .getLogger(BasicPollerPresenceWatcher.class);
+
+    /**
+     * Delay before starting the presence watcher task for the first time.
+     */
+    private static final long INITIAL_PRESENCE_WATCHER_DELAY = 10000L;
+
+    /**
+     * Period for the presence watcher timer.
+     */
+    private static final long PRESENCE_WATCHER_PERIOD = 60000L;
+
+    /**
+     * Instance of IRCAPi.
+     */
+    private final IRCApi irc;
+
+    /**
+     * Connection state instance.
+     */
+    private final IIRCState connectionState;
+
+    /**
+     * The persistent presence operation set used to issue presence updates.
+     */
+    private final OperationSetPersistentPresenceIrcImpl operationSet;
+
+    /**
+     * Synchronized set of nicks to watch for presence changes.
+     */
+    private final SortedSet<String> nickWatchList;
+
+    /**
+     * Constructor.
+     *
+     * @param irc the IRCApi instance
+     * @param connectionState the connection state
+     * @param operationSet the persistent presence operation set
+     * @param nickWatchList the nick watch list
+     * @param serverIdentity the server identity
+     */
+    public BasicPollerPresenceWatcher(final IRCApi irc,
+        final IIRCState connectionState,
+        final OperationSetPersistentPresenceIrcImpl operationSet,
+        final SortedSet<String> nickWatchList,
+        final AtomicReference<String> serverIdentity)
+    {
+        if (irc == null)
+        {
+            throw new IllegalArgumentException("irc cannot be null");
+        }
+        this.irc = irc;
+        if (connectionState == null)
+        {
+            throw new IllegalArgumentException("connectionState cannot be null");
+        }
+        this.connectionState = connectionState;
+        if (operationSet == null)
+        {
+            throw new IllegalArgumentException("operationSet cannot be null");
+        }
+        this.operationSet = operationSet;
+        if (nickWatchList == null)
+        {
+            throw new IllegalArgumentException("nickWatchList cannot be null");
+        }
+        this.nickWatchList = nickWatchList;
+        setUpPresenceWatcher(serverIdentity);
+    }
+
+    /**
+     * Set up a timer for watching the presence of nicks in the watch list.
+     */
+    private void setUpPresenceWatcher(
+        final AtomicReference<String> serverIdentity)
+    {
+        // FIFO query list to be shared between presence watcher task and
+        // presence reply listener.
+        final List<List<String>> queryList =
+            Collections.synchronizedList(new LinkedList<List<String>>());
+        final Timer presenceWatcher = new Timer();
+        irc.addListener(new PresenceReplyListener(presenceWatcher, queryList));
+        final PresenceWatcherTask task =
+            new PresenceWatcherTask(this.nickWatchList, queryList,
+                serverIdentity);
+        presenceWatcher.schedule(task, INITIAL_PRESENCE_WATCHER_DELAY,
+            PRESENCE_WATCHER_PERIOD);
+        LOGGER.trace("Basic Poller presence watcher set up.");
+    }
+
+    @Override
+    public void add(String nick)
+    {
+        this.nickWatchList.add(nick);
+    }
+
+    @Override
+    public void remove(String nick)
+    {
+        this.nickWatchList.remove(nick);
+    }
+
+    /**
+     * Task for watching nick presence.
+     *
+     * @author Danny van Heumen
+     */
+    private final class PresenceWatcherTask extends TimerTask
+    {
+        /**
+         * Static overhead for ISON response message.
+         *
+         * Additional 10 chars extra overhead as fail-safe, as I was not able to
+         * find the exact number in the overhead computation.
+         */
+        private static final int ISON_RESPONSE_STATIC_MESSAGE_OVERHEAD = 18;
+
+        /**
+         * List containing nicks that must be watched.
+         */
+        private final SortedSet<String> watchList;
+
+        /**
+         * FIFO list storing each ISON query that is sent, for use when
+         * responses return.
+         */
+        private final List<List<String>> queryList;
+
+        /**
+         * Reference to the current server identity.
+         */
+        private final AtomicReference<String> serverIdentity;
+
+        /**
+         * Constructor.
+         *
+         * @param watchList the list of nicks to watch
+         * @param queryList list containing list of nicks of each ISON query
+         * @param serverIdentity container with the current server identity for
+         *            use in overhead calculation
+         */
+        public PresenceWatcherTask(final SortedSet<String> watchList,
+            final List<List<String>> queryList,
+            final AtomicReference<String> serverIdentity)
+        {
+            if (watchList == null)
+            {
+                throw new IllegalArgumentException("watchList cannot be null");
+            }
+            this.watchList = watchList;
+            if (queryList == null)
+            {
+                throw new IllegalArgumentException("queryList cannot be null");
+            }
+            this.queryList = queryList;
+            if (serverIdentity == null)
+            {
+                throw new IllegalArgumentException(
+                    "serverIdentity reference cannot be null");
+            }
+            this.serverIdentity = serverIdentity;
+        }
+
+        /**
+         * The implementation of the task.
+         */
+        @Override
+        public void run()
+        {
+            if (this.watchList.isEmpty())
+            {
+                LOGGER.trace("Watch list is empty. Not querying for online "
+                    + "presence.");
+                return;
+            }
+            if (this.serverIdentity.get() == null)
+            {
+                LOGGER.trace("Server identity not available yet. Skipping "
+                    + "this presence status query.");
+                return;
+            }
+            LOGGER
+                .trace("Watch list contains nicks: querying presence status.");
+            final StringBuilder query = new StringBuilder();
+            final LinkedList<String> list;
+            synchronized (this.watchList)
+            {
+                list = new LinkedList<String>(this.watchList);
+            }
+            LinkedList<String> nicks = new LinkedList<String>();
+            // The ISON reply contains the most overhead, so base the maximum
+            // number of nicks limit on that.
+            final int maxQueryLength =
+                MessageManager.IRC_PROTOCOL_MAXIMUM_MESSAGE_SIZE - overhead();
+            for (String nick : list)
+            {
+                if (query.length() + nick.length() >= maxQueryLength)
+                {
+                    this.queryList.add(nicks);
+                    BasicPollerPresenceWatcher.this.irc
+                        .rawMessage(createQuery(query));
+                    // Initialize new data types
+                    query.delete(0, query.length());
+                    nicks = new LinkedList<String>();
+                }
+                query.append(nick);
+                query.append(' ');
+                nicks.add(nick);
+            }
+            if (query.length() > 0)
+            {
+                // Send remaining entries.
+                this.queryList.add(nicks);
+                BasicPollerPresenceWatcher.this.irc
+                    .rawMessage(createQuery(query));
+            }
+        }
+
+        /**
+         * Create an ISON query from the StringBuilder containing the list of
+         * nicks.
+         *
+         * @param nicklist the list of nicks as a StringBuilder instance
+         * @return returns the ISON query string
+         */
+        private String createQuery(final StringBuilder nicklist)
+        {
+            return "ISON " + nicklist;
+        }
+
+        /**
+         * Calculate overhead for ISON response message.
+         *
+         * @return returns amount of overhead in response message
+         */
+        private int overhead()
+        {
+            return ISON_RESPONSE_STATIC_MESSAGE_OVERHEAD
+                + this.serverIdentity.get().length()
+                + BasicPollerPresenceWatcher.this.connectionState.getNickname()
+                    .length();
+        }
+    }
+
+    /**
+     * Presence reply listener.
+     *
+     * Listener that acts on various replies that give an indication of actual
+     * presence or presence changes, such as RPL_ISON and ERR_NOSUCHNICKCHAN.
+     *
+     * @author Danny van Heumen
+     */
+    private final class PresenceReplyListener
+        extends AbstractIrcMessageListener
+    {
+        /**
+         * Reply for ISON query.
+         */
+        private static final int RPL_ISON = 303;
+
+        /**
+         * Error reply in case nick does not exist on server.
+         */
+        private static final int ERR_NOSUCHNICK = 401;
+
+        /**
+         * Timer for presence watcher task.
+         */
+        private final Timer timer;
+
+        /**
+         * FIFO list containing list of nicks for each query.
+         */
+        private final List<List<String>> queryList;
+
+        /**
+         * Constructor.
+         *
+         * @param timer Timer for presence watcher task
+         * @param queryList List of executed queries with expected nicks lists.
+         */
+        public PresenceReplyListener(final Timer timer,
+            final List<List<String>> queryList)
+        {
+            super(BasicPollerPresenceWatcher.this.irc,
+                BasicPollerPresenceWatcher.this.connectionState);
+            if (timer == null)
+            {
+                throw new IllegalArgumentException("timer cannot be null");
+            }
+            this.timer = timer;
+            if (queryList == null)
+            {
+                throw new IllegalArgumentException("queryList cannot be null");
+            }
+            this.queryList = queryList;
+        }
+
+        /**
+         * Update nick watch list upon receiving a nick change message for a
+         * nick that is on the watch list.
+         *
+         * NOTE: This nick change event could be handled earlier than the
+         * handler that fires the contact rename event. This will result in a
+         * missed presence update. However, since the nick change was just
+         * announced, it is reasonable to assume that the user is still online.
+         *
+         * @param msg the nick message
+         */
+        @Override
+        public void onNickChange(final NickMessage msg)
+        {
+            if (msg == null || msg.getSource() == null)
+            {
+                return;
+            }
+            final String oldNick = msg.getSource().getNick();
+            final String newNick = msg.getNewNick();
+            if (oldNick == null || newNick == null)
+            {
+                LOGGER.error("Incomplete nick change message. Old nick: '"
+                    + oldNick + "', new nick: '" + newNick + "'.");
+                return;
+            }
+            synchronized (BasicPollerPresenceWatcher.this.nickWatchList)
+            {
+                if (BasicPollerPresenceWatcher.this.nickWatchList
+                    .contains(oldNick))
+                {
+                    update(oldNick, IrcStatusEnum.OFFLINE);
+                }
+                if (BasicPollerPresenceWatcher.this.nickWatchList
+                    .contains(newNick))
+                {
+                    update(newNick, IrcStatusEnum.ONLINE);
+                }
+            }
+        }
+
+        /**
+         * Message handling for RPL_ISON message and other indicators.
+         *
+         * @param msg the message
+         */
+        @Override
+        public void onServerNumericMessage(final ServerNumericMessage msg)
+        {
+            if (msg == null || msg.getNumericCode() == null)
+            {
+                return;
+            }
+            switch (msg.getNumericCode())
+            {
+            case RPL_ISON:
+                final String[] nicks = msg.getText().substring(1).split(" ");
+                final List<String> offline;
+                if (this.queryList.isEmpty())
+                {
+                    // If no query list exists, we can only update nicks that
+                    // are online, since we do not know who we have actually
+                    // queried for.
+                    offline = new LinkedList<String>();
+                }
+                else
+                {
+                    offline = this.queryList.remove(0);
+                }
+                for (String nick : nicks)
+                {
+                    update(nick, IrcStatusEnum.ONLINE);
+                    offline.remove(nick);
+                }
+                for (String nick : offline)
+                {
+                    update(nick, IrcStatusEnum.OFFLINE);
+                }
+                break;
+            case ERR_NOSUCHNICK:
+                final String errortext = msg.getText();
+                final int idx = errortext.indexOf(' ');
+                if (idx == -1)
+                {
+                    LOGGER.info("ERR_NOSUCHNICK message does not have "
+                        + "expected format.");
+                    return;
+                }
+                final String errNick = errortext.substring(0, idx);
+                update(errNick, IrcStatusEnum.OFFLINE);
+                break;
+            default:
+                break;
+            }
+        }
+
+        /**
+         * Upon receiving a private message from a user, conclude that the user
+         * must then be online and update its presence status.
+         *
+         * @param msg the message
+         */
+        @Override
+        public void onUserPrivMessage(final UserPrivMsg msg)
+        {
+            if (msg == null || msg.getSource() == null)
+            {
+                return;
+            }
+            final IRCUser user = msg.getSource();
+            update(user.getNick(), IrcStatusEnum.ONLINE);
+        }
+
+        /**
+         * Upon receiving a notice from a user, conclude that the user
+         * must then be online and update its presence status.
+         *
+         * @param msg the message
+         */
+        @Override
+        public void onUserNotice(final UserNotice msg)
+        {
+            if (msg == null || msg.getSource() == null)
+            {
+                return;
+            }
+            final IRCUser user = msg.getSource();
+            update(user.getNick(), IrcStatusEnum.ONLINE);
+        }
+
+        /**
+         * Upon receiving an action from a user, conclude that the user
+         * must then be online and update its presence status.
+         *
+         * @param msg the message
+         */
+        @Override
+        public void onUserAction(final UserActionMsg msg)
+        {
+            if (msg == null || msg.getSource() == null)
+            {
+                return;
+            }
+            final IRCUser user = msg.getSource();
+            update(user.getNick(), IrcStatusEnum.ONLINE);
+        }
+
+        /**
+         * Handler for channel join events.
+         */
+        @Override
+        public void onChannelJoin(final ChanJoinMessage msg)
+        {
+            if (msg == null || msg.getSource() == null)
+            {
+                return;
+            }
+            final String user = msg.getSource().getNick();
+            update(user, IrcStatusEnum.ONLINE);
+        }
+
+        /**
+         * Handler for user quit events.
+         *
+         * @param msg the quit message
+         */
+        @Override
+        public void onUserQuit(final QuitMessage msg)
+        {
+            super.onUserQuit(msg);
+            final String user = msg.getSource().getNick();
+            if (user == null)
+            {
+                return;
+            }
+            if (localUser(user))
+            {
+                // Stop presence watcher task.
+                this.timer.cancel();
+                updateAll(IrcStatusEnum.OFFLINE);
+            }
+            else
+            {
+                update(user, IrcStatusEnum.OFFLINE);
+            }
+        }
+
+        /**
+         * In case a fatal error occurs, remove the listener.
+         *
+         * @param msg the error message
+         */
+        @Override
+        public void onError(final ErrorMessage msg)
+        {
+            super.onError(msg);
+            // Stop presence watcher task.
+            this.timer.cancel();
+            updateAll(IrcStatusEnum.OFFLINE);
+        }
+
+        /**
+         * Update the status of a single nick.
+         *
+         * @param nick the nick to update
+         * @param status the new status
+         */
+        private void update(final String nick, final IrcStatusEnum status)
+        {
+            // User is some other user, so check if we are watching that nick.
+            if (!BasicPollerPresenceWatcher.this.nickWatchList.contains(nick))
+            {
+                return;
+            }
+            BasicPollerPresenceWatcher.this.operationSet
+                .updateNickContactPresence(nick, status);
+        }
+
+        /**
+         * Update the status of all contacts in the nick watch list.
+         *
+         * @param status the new status
+         */
+        private void updateAll(final IrcStatusEnum status)
+        {
+            final LinkedList<String> list;
+            synchronized (BasicPollerPresenceWatcher.this.nickWatchList)
+            {
+                list =
+                    new LinkedList<String>(
+                        BasicPollerPresenceWatcher.this.nickWatchList);
+            }
+            for (String nick : list)
+            {
+                BasicPollerPresenceWatcher.this.operationSet
+                    .updateNickContactPresence(nick, status);
+            }
+        }
+    }
+}
diff --git a/src/net/java/sip/communicator/impl/protocol/irc/PresenceManager.java b/src/net/java/sip/communicator/impl/protocol/irc/PresenceManager.java
index 3eb22fd..000fa13 100644
--- a/src/net/java/sip/communicator/impl/protocol/irc/PresenceManager.java
+++ b/src/net/java/sip/communicator/impl/protocol/irc/PresenceManager.java
@@ -13,7 +13,6 @@ import java.util.concurrent.atomic.*;
 import net.java.sip.communicator.util.*;
 
 import com.ircclouds.irc.api.*;
-import com.ircclouds.irc.api.domain.*;
 import com.ircclouds.irc.api.domain.messages.*;
 import com.ircclouds.irc.api.state.*;
 
@@ -42,16 +41,6 @@ public class PresenceManager
         .getLogger(PresenceManager.class);
 
     /**
-     * Delay before starting the presence watcher task for the first time.
-     */
-    private static final long INITIAL_PRESENCE_WATCHER_DELAY = 10000L;
-
-    /**
-     * Period for the presence watcher timer.
-     */
-    private static final long PRESENCE_WATCHER_PERIOD = 60000L;
-
-    /**
      * IRC client library instance.
      *
      * Instance must be thread-safe!
@@ -69,9 +58,9 @@ public class PresenceManager
     private final OperationSetPersistentPresenceIrcImpl operationSet;
 
     /**
-     * Synchronized set of nicks to watch for presence changes.
+     * Presence watcher.
      */
-    private final SortedSet<String> nickWatchList;
+    private final PresenceWatcher watcher;
 
     /**
      * Maximum away message length according to server ISUPPORT instructions.
@@ -133,42 +122,31 @@ public class PresenceManager
             throw new IllegalArgumentException("irc cannot be null");
         }
         this.irc = irc;
+        final SortedSet<String> nickWatchList;
         if (persistentNickWatchList == null)
         {
             // watch list will be non-persistent, since we create an instance at
             // initialization time
-            this.nickWatchList =
+            nickWatchList =
                 Collections.synchronizedSortedSet(new TreeSet<String>());
         }
         else
         {
-            this.nickWatchList = persistentNickWatchList;
+            nickWatchList = persistentNickWatchList;
         }
-        this.irc.addListener(new PresenceListener());
+        this.irc.addListener(new LocalUserPresenceListener());
         this.isupportAwayLen = parseISupportAwayLen(this.connectionState);
         if (config.isContactPresenceTaskEnabled())
         {
-            setUpPresenceWatcher();
+            this.watcher =
+                new BasicPollerPresenceWatcher(this.irc, this.connectionState,
+                    this.operationSet, nickWatchList, this.serverIdentity);
+        }
+        else
+        {
+            // FIXME replace with NOOP watcher for code simplicity?
+            this.watcher = null;
         }
-    }
-
-    /**
-     * Set up a timer for watching the presence of nicks in the watch list.
-     */
-    private void setUpPresenceWatcher()
-    {
-        // FIFO query list to be shared between presence watcher task and
-        // presence reply listener.
-        final List<List<String>> queryList =
-            Collections.synchronizedList(new LinkedList<List<String>>());
-        final Timer presenceWatcher = new Timer();
-        irc.addListener(new PresenceReplyListener(presenceWatcher, queryList));
-        final PresenceWatcherTask task =
-            new PresenceWatcherTask(this.nickWatchList, queryList, this.irc,
-                this.connectionState, this.serverIdentity);
-        presenceWatcher.schedule(task, INITIAL_PRESENCE_WATCHER_DELAY,
-            PRESENCE_WATCHER_PERIOD);
-        LOGGER.trace("Presence watcher set up.");
     }
 
     /**
@@ -316,7 +294,10 @@ public class PresenceManager
      */
     public void addNickWatch(final String nick)
     {
-        this.nickWatchList.add(nick);
+        if (this.watcher != null)
+        {
+            this.watcher.add(nick);
+        }
     }
 
     /**
@@ -326,7 +307,10 @@ public class PresenceManager
      */
     public void removeNickWatch(final String nick)
     {
-        this.nickWatchList.remove(nick);
+        if (this.watcher != null)
+        {
+            this.watcher.remove(nick);
+        }
     }
 
     /**
@@ -335,7 +319,7 @@ public class PresenceManager
      *
      * @author Danny van Heumen
      */
-    private final class PresenceListener
+    private final class LocalUserPresenceListener
         extends AbstractIrcMessageListener
     {
         /**
@@ -352,7 +336,7 @@ public class PresenceManager
         /**
          * Constructor.
          */
-        public PresenceListener()
+        public LocalUserPresenceListener()
         {
             super(PresenceManager.this.irc,
                 PresenceManager.this.connectionState);
@@ -400,461 +384,7 @@ public class PresenceManager
     }
 
     /**
-     * Task for watching nick presence.
-     *
-     * @author Danny van Heumen
-     */
-    private static final class PresenceWatcherTask extends TimerTask
-    {
-        /**
-         * Static overhead for ISON response message.
-         *
-         * Additional 10 chars extra overhead as fail-safe, as I was not able to
-         * find the exact number in the overhead computation.
-         */
-        private static final int ISON_RESPONSE_STATIC_MESSAGE_OVERHEAD = 18;
-
-        /**
-         * List containing nicks that must be watched.
-         */
-        private final SortedSet<String> watchList;
-
-        /**
-         * FIFO list storing each ISON query that is sent, for use when
-         * responses return.
-         */
-        private final List<List<String>> queryList;
-
-        /**
-         * IRC instance.
-         */
-        private final IRCApi irc;
-
-        /**
-         * IRC connection state.
-         */
-        private final IIRCState connectionState;
-
-        /**
-         * Reference to the current server identity.
-         */
-        private final AtomicReference<String> serverIdentity;
-
-        /**
-         * Constructor.
-         *
-         * @param watchList the list of nicks to watch
-         * @param queryList list containing list of nicks of each ISON query
-         * @param irc the irc instance
-         * @param connectionState the connection state instance
-         * @param serverIdentity container with the current server identity for
-         *            use in overhead calculation
-         */
-        public PresenceWatcherTask(final SortedSet<String> watchList,
-            final List<List<String>> queryList, final IRCApi irc,
-            final IIRCState connectionState,
-            final AtomicReference<String> serverIdentity)
-        {
-            if (watchList == null)
-            {
-                throw new IllegalArgumentException("watchList cannot be null");
-            }
-            this.watchList = watchList;
-            if (queryList == null)
-            {
-                throw new IllegalArgumentException("queryList cannot be null");
-            }
-            this.queryList = queryList;
-            if (irc == null)
-            {
-                throw new IllegalArgumentException("irc cannot be null");
-            }
-            this.irc = irc;
-            if (connectionState == null)
-            {
-                throw new IllegalArgumentException(
-                    "connectionState cannot be null");
-            }
-            this.connectionState = connectionState;
-            if (serverIdentity == null)
-            {
-                throw new IllegalArgumentException(
-                    "serverIdentity reference cannot be null");
-            }
-            this.serverIdentity = serverIdentity;
-        }
-
-        /**
-         * The implementation of the task.
-         */
-        @Override
-        public void run()
-        {
-            if (this.watchList.isEmpty())
-            {
-                LOGGER.trace("Watch list is empty. Not querying for online "
-                    + "presence.");
-                return;
-            }
-            if (this.serverIdentity.get() == null)
-            {
-                LOGGER.trace("Server identity not available yet. Skipping "
-                    + "this presence status query.");
-                return;
-            }
-            LOGGER
-                .trace("Watch list contains nicks: querying presence status.");
-            final StringBuilder query = new StringBuilder();
-            final LinkedList<String> list;
-            synchronized (this.watchList)
-            {
-                list = new LinkedList<String>(this.watchList);
-            }
-            LinkedList<String> nicks = new LinkedList<String>();
-            // The ISON reply contains the most overhead, so base the maximum
-            // number of nicks limit on that.
-            final int maxQueryLength =
-                MessageManager.IRC_PROTOCOL_MAXIMUM_MESSAGE_SIZE - overhead();
-            for (String nick : list)
-            {
-                if (query.length() + nick.length() >= maxQueryLength)
-                {
-                    this.queryList.add(nicks);
-                    this.irc.rawMessage(createQuery(query));
-                    // Initialize new data types
-                    query.delete(0, query.length());
-                    nicks = new LinkedList<String>();
-                }
-                query.append(nick);
-                query.append(' ');
-                nicks.add(nick);
-            }
-            if (query.length() > 0)
-            {
-                // Send remaining entries.
-                this.queryList.add(nicks);
-                this.irc.rawMessage(createQuery(query));
-            }
-        }
-
-        /**
-         * Create an ISON query from the StringBuilder containing the list of
-         * nicks.
-         *
-         * @param nicklist the list of nicks as a StringBuilder instance
-         * @return returns the ISON query string
-         */
-        private String createQuery(final StringBuilder nicklist)
-        {
-            return "ISON " + nicklist;
-        }
-
-        /**
-         * Calculate overhead for ISON response message.
-         *
-         * @return returns amount of overhead in response message
-         */
-        private int overhead()
-        {
-            return ISON_RESPONSE_STATIC_MESSAGE_OVERHEAD
-                + this.serverIdentity.get().length()
-                + this.connectionState.getNickname().length();
-        }
-    }
-
-    /**
-     * Presence reply listener.
-     *
-     * Listener that acts on various replies that give an indication of actual
-     * presence or presence changes, such as RPL_ISON and ERR_NOSUCHNICKCHAN.
-     *
-     * @author Danny van Heumen
-     */
-    private final class PresenceReplyListener
-        extends AbstractIrcMessageListener
-    {
-        /**
-         * Reply for ISON query.
-         */
-        private static final int RPL_ISON = 303;
-
-        /**
-         * Error reply in case nick does not exist on server.
-         */
-        private static final int ERR_NOSUCHNICK = 401;
-
-        /**
-         * Timer for presence watcher task.
-         */
-        private final Timer timer;
-
-        /**
-         * FIFO list containing list of nicks for each query.
-         */
-        private final List<List<String>> queryList;
-
-        /**
-         * Constructor.
-         *
-         * @param timer Timer for presence watcher task
-         * @param queryList List of executed queries with expected nicks lists.
-         */
-        public PresenceReplyListener(final Timer timer,
-            final List<List<String>> queryList)
-        {
-            super(PresenceManager.this.irc,
-                PresenceManager.this.connectionState);
-            if (timer == null)
-            {
-                throw new IllegalArgumentException("timer cannot be null");
-            }
-            this.timer = timer;
-            if (queryList == null)
-            {
-                throw new IllegalArgumentException("queryList cannot be null");
-            }
-            this.queryList = queryList;
-        }
-
-        /**
-         * Update nick watch list upon receiving a nick change message for a
-         * nick that is on the watch list.
-         *
-         * NOTE: This nick change event could be handled earlier than the
-         * handler that fires the contact rename event. This will result in a
-         * missed presence update. However, since the nick change was just
-         * announced, it is reasonable to assume that the user is still online.
-         *
-         * @param msg the nick message
-         */
-        @Override
-        public void onNickChange(final NickMessage msg)
-        {
-            if (msg == null || msg.getSource() == null)
-            {
-                return;
-            }
-            final String oldNick = msg.getSource().getNick();
-            final String newNick = msg.getNewNick();
-            if (oldNick == null || newNick == null)
-            {
-                LOGGER.error("Incomplete nick change message. Old nick: '"
-                    + oldNick + "', new nick: '" + newNick + "'.");
-                return;
-            }
-            synchronized (PresenceManager.this.nickWatchList)
-            {
-                if (PresenceManager.this.nickWatchList.contains(oldNick))
-                {
-                    update(oldNick, IrcStatusEnum.OFFLINE);
-                }
-                if (PresenceManager.this.nickWatchList.contains(newNick))
-                {
-                    update(newNick, IrcStatusEnum.ONLINE);
-                }
-            }
-        }
-
-        /**
-         * Message handling for RPL_ISON message and other indicators.
-         *
-         * @param msg the message
-         */
-        @Override
-        public void onServerNumericMessage(final ServerNumericMessage msg)
-        {
-            if (msg == null || msg.getNumericCode() == null)
-            {
-                return;
-            }
-            switch (msg.getNumericCode())
-            {
-            case RPL_ISON:
-                final String[] nicks = msg.getText().substring(1).split(" ");
-                final List<String> offline;
-                if (this.queryList.isEmpty())
-                {
-                    // If no query list exists, we can only update nicks that
-                    // are online, since we do not know who we have actually
-                    // queried for.
-                    offline = new LinkedList<String>();
-                }
-                else
-                {
-                    offline = this.queryList.remove(0);
-                }
-                for (String nick : nicks)
-                {
-                    update(nick, IrcStatusEnum.ONLINE);
-                    offline.remove(nick);
-                }
-                for (String nick : offline)
-                {
-                    update(nick, IrcStatusEnum.OFFLINE);
-                }
-                break;
-            case ERR_NOSUCHNICK:
-                final String errortext = msg.getText();
-                final int idx = errortext.indexOf(' ');
-                if (idx == -1)
-                {
-                    LOGGER.info("ERR_NOSUCHNICK message does not have "
-                        + "expected format.");
-                    return;
-                }
-                final String errNick = errortext.substring(0, idx);
-                update(errNick, IrcStatusEnum.OFFLINE);
-                break;
-            default:
-                break;
-            }
-        }
-
-        /**
-         * Upon receiving a private message from a user, conclude that the user
-         * must then be online and update its presence status.
-         *
-         * @param msg the message
-         */
-        @Override
-        public void onUserPrivMessage(final UserPrivMsg msg)
-        {
-            if (msg == null || msg.getSource() == null)
-            {
-                return;
-            }
-            final IRCUser user = msg.getSource();
-            update(user.getNick(), IrcStatusEnum.ONLINE);
-        }
-
-        /**
-         * Upon receiving a notice from a user, conclude that the user
-         * must then be online and update its presence status.
-         *
-         * @param msg the message
-         */
-        @Override
-        public void onUserNotice(final UserNotice msg)
-        {
-            if (msg == null || msg.getSource() == null)
-            {
-                return;
-            }
-            final IRCUser user = msg.getSource();
-            update(user.getNick(), IrcStatusEnum.ONLINE);
-        }
-
-        /**
-         * Upon receiving an action from a user, conclude that the user
-         * must then be online and update its presence status.
-         *
-         * @param msg the message
-         */
-        @Override
-        public void onUserAction(final UserActionMsg msg)
-        {
-            if (msg == null || msg.getSource() == null)
-            {
-                return;
-            }
-            final IRCUser user = msg.getSource();
-            update(user.getNick(), IrcStatusEnum.ONLINE);
-        }
-
-        /**
-         * Handler for channel join events.
-         */
-        @Override
-        public void onChannelJoin(final ChanJoinMessage msg)
-        {
-            if (msg == null || msg.getSource() == null)
-            {
-                return;
-            }
-            final String user = msg.getSource().getNick();
-            update(user, IrcStatusEnum.ONLINE);
-        }
-
-        /**
-         * Handler for user quit events.
-         *
-         * @param msg the quit message
-         */
-        @Override
-        public void onUserQuit(final QuitMessage msg)
-        {
-            super.onUserQuit(msg);
-            final String user = msg.getSource().getNick();
-            if (user == null)
-            {
-                return;
-            }
-            if (localUser(user))
-            {
-                // Stop presence watcher task.
-                this.timer.cancel();
-                updateAll(IrcStatusEnum.OFFLINE);
-            }
-            else
-            {
-                update(user, IrcStatusEnum.OFFLINE);
-            }
-        }
-
-        /**
-         * In case a fatal error occurs, remove the listener.
-         *
-         * @param msg the error message
-         */
-        @Override
-        public void onError(final ErrorMessage msg)
-        {
-            super.onError(msg);
-            // Stop presence watcher task.
-            this.timer.cancel();
-            updateAll(IrcStatusEnum.OFFLINE);
-        }
-
-        /**
-         * Update the status of a single nick.
-         *
-         * @param nick the nick to update
-         * @param status the new status
-         */
-        private void update(final String nick, final IrcStatusEnum status)
-        {
-            // User is some other user, so check if we are watching that nick.
-            if (!PresenceManager.this.nickWatchList.contains(nick))
-            {
-                return;
-            }
-            PresenceManager.this.operationSet.updateNickContactPresence(nick,
-                status);
-        }
-
-        /**
-         * Update the status of all contacts in the nick watch list.
-         *
-         * @param status the new status
-         */
-        private void updateAll(final IrcStatusEnum status)
-        {
-            final LinkedList<String> list;
-            synchronized (PresenceManager.this.nickWatchList)
-            {
-                list =
-                    new LinkedList<String>(PresenceManager.this.nickWatchList);
-            }
-            for (String nick : list)
-            {
-                PresenceManager.this.operationSet.updateNickContactPresence(
-                    nick, status);
-            }
-        }
-    }
-
-    /**
-     * Listener for WHOIS replies, such that we can query information of the
+     * Listener for WHOIS replies, such that we can receive information of the
      * user that we are querying.
      *
      * @author Danny van Heumen
diff --git a/src/net/java/sip/communicator/impl/protocol/irc/PresenceWatcher.java b/src/net/java/sip/communicator/impl/protocol/irc/PresenceWatcher.java
new file mode 100644
index 0000000..dfd917d
--- /dev/null
+++ b/src/net/java/sip/communicator/impl/protocol/irc/PresenceWatcher.java
@@ -0,0 +1,32 @@
+/*
+ * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.impl.protocol.irc;
+
+/**
+ * Interface of the presence watcher.
+ * 
+ * This interface defines the requirements of a presence watcher. The watcher is
+ * used to update contact presence for a selection of nicks.
+ * 
+ * @author Danny van Heumen
+ */
+public interface PresenceWatcher
+{
+    /**
+     * Add a nick to the list.
+     *
+     * @param nick the nick
+     */
+    void add(String nick);
+
+    /**
+     * Remove a nick from the list.
+     *
+     * @param nick the nick
+     */
+    void remove(String nick);
+}