diff -r 62043f5f7c67 -r 0e29eec2df5c project_files/Android-build/SDL-android-project/src/org/hedgewars/hedgeroid/netplay/ObservableLinkedHashMap.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/project_files/Android-build/SDL-android-project/src/org/hedgewars/hedgeroid/netplay/ObservableLinkedHashMap.java	Thu Jul 19 18:58:18 2012 +0200
@@ -0,0 +1,72 @@
+package org.hedgewars.hedgeroid.netplay;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A map of items, sorted by time of insertion (earliest first). 
+ * Observers can be notified about insertions, deletions and changes (which don't change the order).
+ * This is useful for e.g. the lists of current rooms and players, because it allows easy addition
+ * and removal of entries on the one side, as well as reaction to these events by UI elements.
+ */
+public class ObservableLinkedHashMap<K,V> {
+	private LinkedHashMap<K,V> map = new LinkedHashMap<K,V>();
+	private List<Observer<K,V>> observers = new LinkedList<Observer<K,V>>();
+	
+	public Collection<V> getValues() {
+		return Collections.unmodifiableCollection(map.values());
+	}
+	
+	public Map<K,V> getMap() {
+		return Collections.unmodifiableMap(map);
+	}
+	
+	public void observe(Observer<K,V> observer) {
+		observers.add(observer);
+	}
+	
+	public void unobserve(Observer<K,V> observer) {
+		observers.remove(observer);
+	}
+	
+	// TODO ugh
+	public void clear() {
+		while(!map.isEmpty()) {
+			remove(map.keySet().iterator().next());
+		}
+	}
+	
+	public void put(K key, V value) {
+		V oldValue = map.put(key, value);
+		Map<K,V> unmodifiableMap = Collections.unmodifiableMap(map);
+		if(oldValue != null) {
+			for(Observer<K,V> o : observers) {
+				o.itemReplaced(unmodifiableMap, key, oldValue, value);
+			}
+		} else {
+			for(Observer<K,V> o : observers) {
+				o.itemAdded(unmodifiableMap, key, value);
+			}
+		}
+	}
+	
+	public void remove(K key) {
+		V oldValue = map.remove(key);
+		if(oldValue != null) {
+			Map<K,V> unmodifiableMap = Collections.unmodifiableMap(map);
+			for(Observer<K,V> o : observers) {
+				o.itemRemoved(unmodifiableMap, key, oldValue);
+			}
+		}
+	}
+
+	public static interface Observer<K,V> {
+		void itemAdded(Map<K,V> map, K key, V value);
+		void itemRemoved(Map<K,V> map, K key, V oldValue);
+		void itemReplaced(Map<K,V> map, K key, V oldValue, V newValue);
+	}
+}