Add channel topic listeners

Change-Id: Id72f5f4ca191592ff0b04883e62de2263b3ebbdc
Reviewed-on: http://gerrit.dmdirc.com/656
Automatic-Compile: Gregory Holmes <greg@dmdirc.com>
Reviewed-by: Gregory Holmes <greg@dmdirc.com>

src/com/dmdirc/Channel.java

@@ -28,6 +28,7 @@ import com.dmdirc.commandparser.CommandManager;
 import com.dmdirc.commandparser.CommandType;
 import com.dmdirc.config.ConfigManager;
 import com.dmdirc.interfaces.ConfigChangeListener;
+import com.dmdirc.interfaces.TopicChangeListener;
 import com.dmdirc.parser.interfaces.ChannelClientInfo;
 import com.dmdirc.parser.interfaces.ChannelInfo;
 import com.dmdirc.parser.interfaces.ClientInfo;
@@ -461,39 +462,6 @@ public class Channel extends MessageTarget implements ConfigChangeListener,
         }
     }
 
-    /**
-     * Adds the specified topic to this channel's topic list.
-     *
-     * @param topic The topic to be added.
-     */
-    public void addTopic(final Topic topic) {
-        topics.add(topic);
-        updateTitle();
-    }
-
-    /**
-     * Retrieve the topics that have been seen on this channel.
-     *
-     * @return A list of topics that have been seen on this channel, including
-     * the current one.
-     */
-    public List<Topic> getTopics() {
-        return topics.getList();
-    }
-
-    /**
-     * Returns the current topic for this channel.
-     * 
-     * @return Current channel topic
-     */
-    public Topic getCurrentTopic() {
-        if (channelInfo.getTopic().isEmpty()) {
-            return null;
-        }
-        return new Topic(channelInfo.getTopic(), channelInfo.getTopicSetter(),
-                channelInfo.getTopicTime());
-    }
-
     /** {@inheritDoc} */
     @Override
     public void configChanged(final String domain, final String key) {
@@ -592,6 +560,71 @@ public class Channel extends MessageTarget implements ConfigChangeListener,
         messageArgs.add(channelInfo.getName());
     }
 
+    // ---------------------------------------------------- TOPIC HANDLING -----
+
+    /**
+     * Adds the specified topic to this channel's topic list.
+     *
+     * @param topic The topic to be added.
+     */
+    public void addTopic(final Topic topic) {
+        topics.add(topic);
+        updateTitle();
+
+        synchronized (listeners) {
+            for (TopicChangeListener listener : listeners.get(TopicChangeListener.class)) {
+                listener.topicChanged(this, topic);
+            }
+        }
+    }
+
+    /**
+     * Retrieve the topics that have been seen on this channel.
+     *
+     * @return A list of topics that have been seen on this channel, including
+     * the current one.
+     */
+    public List<Topic> getTopics() {
+        return topics.getList();
+    }
+
+    /**
+     * Returns the current topic for this channel.
+     *
+     * @return Current channel topic
+     */
+    public Topic getCurrentTopic() {
+        if (channelInfo.getTopic().isEmpty()) {
+            return null;
+        }
+        return new Topic(channelInfo.getTopic(), channelInfo.getTopicSetter(),
+                channelInfo.getTopicTime());
+    }
+
+    /**
+     * Adds a new topic change listener to this channel.
+     *
+     * @param listener The listener to be added
+     * @since 0.6.3
+     */
+    public void addTopicChangeListener(final TopicChangeListener listener) {
+        synchronized (listeners) {
+            listeners.add(TopicChangeListener.class, listener);
+        }
+    }
+
+    /**
+     * Removes an existing topic change listener from this channel.
+     *
+     * @param listener The listener to be removed
+     * @since 0.6.3
+     */
+    public void removeTopicChangeListener(final TopicChangeListener listener) {
+        synchronized (listeners) {
+            listeners.remove(TopicChangeListener.class, listener);
+        }
+    }
+
     // ------------------------------------------ PARSER METHOD DELEGATION -----
 
     /**
@@ -603,4 +636,14 @@ public class Channel extends MessageTarget implements ConfigChangeListener,
     public void setTopic(final String topic) {
         channelInfo.setTopic(topic);
     }
+
+    /**
+     * Retrieves the maximum length that a topic on this channel can be.
+     *
+     * @return The maximum length that this channel's topic may be
+     * @since 0.6.3
+     */
+    public int getMaxTopicLength() {
+        return server.getParser().getMaxTopicLength();
+    }
 }

src/com/dmdirc/interfaces/TopicChangeListener.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2006-2010 Chris Smith, Shane Mc Cormack, Gregory Holmes
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.dmdirc.interfaces;
+
+import com.dmdirc.Channel;
+import com.dmdirc.Topic;
+
+/**
+ * An interface for objects interested in receiving topic change events from
+ * a {@link Channel}.
+ *
+ * @since 0.6.3
+ * @author chris
+ */
+public interface TopicChangeListener {
+
+    /**
+     * Called whenever a topic is changed.
+     *
+     * @param channel The channel whose topic has been changed
+     * @param topic The new topic of the channel
+     */
+    void topicChanged(final Channel channel, final Topic topic);
+
+}