Add ListenerSupport class.

diff --git a/src/net/pterodactylus/util/event/ListenerSupport.java b/src/net/pterodactylus/util/event/ListenerSupport.java
new file mode 100644 (file)
index 0000000..1b11296
--- /dev/null
+++ b/src/net/pterodactylus/util/event/ListenerSupport.java
@@ -0,0 +1,102 @@
+/*
+ * jSite-next - ListenerSupport.java -
+ * Copyright © 2008 David Roden
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+package net.pterodactylus.util.event;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Helper class to ease listener management.
+ *
+ * @param <S>
+ *            The type of the source
+ * @param <L>
+ *            The type of the listeners
+ * @author David ‘Bombe’ Roden &lt;bombe@freenetproject.org&gt;
+ */
+public class ListenerSupport<S, L> {
+
+       /** The source of the events. */
+       private final S source;
+
+       /** The list of registered listeners. */
+       private final List<L> listeners = new ArrayList<L>();
+
+       /**
+        * Creates a new listener support.
+        *
+        * @param source
+        *            The source of all events
+        */
+       public ListenerSupport(S source) {
+               this.source = source;
+       }
+
+       /**
+        * Adds a listener to the list of registered listeners.
+        *
+        * @param listener
+        *            The listener to add
+        */
+       public void addListener(L listener) {
+               synchronized (listeners) {
+                       listeners.add(listener);
+               }
+       }
+
+       /**
+        * Removes a listener from the list of registered listeners.
+        *
+        * @param listener
+        *            The listener to remove
+        */
+       public void removeListener(L listener) {
+               synchronized (listeners) {
+                       listeners.remove(listener);
+               }
+       }
+
+       //
+       // PROTECTED METHODS
+       //
+
+       /**
+        * Returns the source of all events.
+        *
+        * @return The source of all events
+        */
+       protected S getSource() {
+               return source;
+       }
+
+       /**
+        * Returns a list of all listeners. This list is a copy of the internally
+        * kept list and as thus will not be modified by calls to
+        * {@link #addListener(Object)} or {@link #removeListener(Object)}.
+        *
+        * @return The list of all listeners
+        */
+       protected List<L> getListeners() {
+               synchronized (listeners) {
+                       return new ArrayList<L>(listeners);
+               }
+       }
+
+}