Added isEmpty().

git-svn-id: https://samskivert.googlecode.com/svn/trunk@2605 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/util/Invoker.java

@@ -153,6 +153,17 @@ public class Invoker extends LoopingThread
         _queue.append(unit);
     }
 
+    /**
+     * Returns true if this invoker has no pending units, false if it has pending units.
+     * <em>Note:</em> this does not account for whether a unit is <em>currently</em> being
+     * processed, so if you want to guarantee that an invoker is empty, it's best to call this
+     * method in a unit being processed by that invoker.
+     */
+    public boolean isEmpty ()
+    {
+        return _queue.size() == 0;
+    }
+
     // from RunQueue
     public void postRunnable (final Runnable r)
     {