Added convenience class to facilitate performing a one-time server-side

action when a game ends.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@2071 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/parlor/game/GameWatcher.java

@@ -0,0 +1,54 @@
+//
+// $Id: GameWatcher.java,v 1.1 2002/12/16 05:06:58 shaper Exp $
+
+package com.threerings.parlor.game;
+
+import com.threerings.presents.dobj.AttributeChangeListener;
+import com.threerings.presents.dobj.AttributeChangedEvent;
+
+import com.threerings.crowd.data.PlaceObject;
+import com.threerings.crowd.server.PlaceManager;
+import com.threerings.crowd.server.PlaceRegistry;
+
+/**
+ * An abstract convenience class used server-side to keep an eye on a game
+ * and perform a one-time game-over activity when the game ends.  Classes
+ * that care to make use of the game watcher should create an instance,
+ * implement {@link #gameDidEnd}, and pass the instance to the place
+ * registry in the call to {@link PlaceRegistry#createPlace} when the
+ * puzzle is created.
+ */
+public abstract class GameWatcher
+    implements PlaceRegistry.CreationObserver, AttributeChangeListener
+{
+    // documentation inherited
+    public void placeCreated (PlaceObject place, PlaceManager pmgr)
+    {
+        _gameobj = (GameObject)place;
+        _gameobj.addListener(this);
+    }
+
+    // documentation inherited
+    public void attributeChanged (AttributeChangedEvent event)
+    {
+        if (event.getName().equals(GameObject.STATE)) {
+            // if we transitioned to a non-in-play state, the game has
+            // completed
+            if (!_gameobj.isInPlay()) {
+                gameDidEnd(_gameobj);
+                // clean up
+                _gameobj.removeListener(this);
+                _gameobj = null;
+            }
+        }
+    }
+
+    /**
+     * Called when the game ends to give derived classes a chance to
+     * engage in their game-over antics.
+     */
+    protected abstract void gameDidEnd (GameObject gameobj);
+
+    /** The game object we're observing. */
+    protected GameObject _gameobj;
+}