add EventDispatcher

vtm/src/org/oscim/event/EventDispatcher.java

@@ -0,0 +1,86 @@
+package org.oscim.event;
+
+import org.oscim.utils.pool.LList;
+
+/**
+ * The Class EventDispatcher.
+ * 
+ * Events MUST be dispached from main-loop! To add events from other
+ * threads use:
+ * Map.post(new Runnable(){ public void run(tell(event,data);)};);
+ * 
+ * @param <T> the event source type
+ * @param <E> the event 'data' type
+ */
+public class EventDispatcher<T, E> {
+
+	/**
+	 * Generic event-listener interface.
+	 * 
+	 * @param <E> the type of event 'data'
+	 */
+	public interface Listener<E> {
+
+		/**
+		 * The onEvent handler to be implemented by Listeners.
+		 * 
+		 * @param source the event source
+		 * @param event the event object/type
+		 * @param data, some object involved in this event
+		 */
+		public void onEvent(Object source, Event event, E data);
+	}
+
+	/**
+	 * The Class Event to be subclassed by event-producers. Should be used
+	 * to distinguish the type of event when more than one is produced.
+	 */
+	public static class Event {
+		// nothing here
+	}
+
+	/** The event source object. */
+	protected final T mSource;
+
+	/** The list of listeners. */
+	protected LList<Listener<E>> mListeners;
+
+	/**
+	 * Instantiates a new event dispatcher.
+	 * 
+	 * @param source the event-source
+	 */
+	public EventDispatcher(T source) {
+		mSource = source;
+	}
+
+	/**
+	 * Bind listener for event notifications.
+	 */
+	public void bind(Listener<E> listener) {
+		if (LList.find(mListeners, listener) != null) {
+			// throw some poo?
+			return;
+		}
+		mListeners = LList.push(mListeners, new LList<Listener<E>>(listener));
+	}
+
+	/**
+	 * Unbind listener.
+	 */
+	public void unbind(Listener<E> listener) {
+		mListeners = LList.remove(mListeners, listener);
+	}
+
+	/**
+	 * Tell listeners whats going on.
+	 * 
+	 * @param event the event
+	 * @param data the data
+	 */
+	public void tell(Event event, E data) {
+		for (LList<Listener<E>> l = mListeners; l != null; l = l.next) {
+			l.data.onEvent(mSource, event, data);
+		}
+	}
+}