Added convenience class for observing animations and being notified when

each individual animation completes and when all added animations have
completed.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1381 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/media/animation/AnimationWaiter.java

@@ -0,0 +1,63 @@
+//
+// $Id: AnimationWaiter.java,v 1.1 2002/05/21 17:59:11 shaper Exp $
+
+package com.threerings.media.animation;
+
+/**
+ * An abstract class that simplifies a common animation usage case in
+ * which a number of animations are created and the creator would like to
+ * be able to perform specific actions when each animation has completed
+ * (see {@link #animationDidFinish} and/or when all animations are
+ * finished (see {@link #allAnimationsFinished}.)
+ */
+public abstract class AnimationWaiter
+    implements AnimationObserver
+{
+    /**
+     * Adds an animation to the animation waiter for observation.
+     */
+    public void addAnimation (Animation anim)
+    {
+        anim.addAnimationObserver(this);
+        _animCount++;
+    }
+
+    // documentation inherited
+    public void handleEvent (AnimationEvent event)
+    {
+        if (event instanceof AnimationCompletedEvent) {
+            // note that the animation is finished
+            Animation anim = event.getAnimation();
+            animationDidFinish(anim);
+            _animCount--;
+
+            // let derived classes know when all is done
+            if (_animCount == 0) {
+                allAnimationsFinished();
+            }
+        }
+    }
+
+    /**
+     * Called when an animation being observed by the waiter has
+     * completed its business.  Derived classes may wish to override
+     * this method to engage in their unique antics.
+     */
+    protected void animationDidFinish (Animation anim)
+    {
+        // nothing for now
+    }
+
+    /**
+     * Called when all animations being observed by the waiter have
+     * completed their business.  Derived classes may wish to override
+     * this method to engage in their unique antics.
+     */
+    protected void allAnimationsFinished ()
+    {
+        // nothing for now
+    }
+
+    /** The number of animations. */
+    protected int _animCount;
+}