--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/utilities/WorkerThread.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2000-2001 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+package sun.jvm.hotspot.utilities;
+
+/** This class abstracts the notion of a worker thread which is fed
+    tasks in the form of Runnables. */
+
+public class WorkerThread {
+  private volatile boolean done = false;
+  private MessageQueueBackend mqb;
+  private MessageQueue mq;
+
+  public WorkerThread() {
+    mqb = new MessageQueueBackend();
+    mq = mqb.getFirstQueue();
+    new Thread(new MainLoop()).start();
+  }
+
+  /** Runs the given Runnable in the thread represented by this
+      WorkerThread object at an unspecified later time. */
+  public void invokeLater(Runnable runnable) {
+    mq.writeMessage(runnable);
+  }
+
+  /** Can be used to dispose of the internal worker thread. Note that
+      this method may return before the internal worker thread
+      terminates. */
+  public void shutdown() {
+    done = true;
+    mq.writeMessage(new Runnable() { public void run() {} });
+  }
+
+  class MainLoop implements Runnable {
+    private MessageQueue myMq;
+
+    public MainLoop() {
+      myMq = mqb.getSecondQueue();
+    }
+
+    public void run() {
+      while (!done) {
+        Runnable runnable = (Runnable) myMq.readMessage();
+        try {
+          runnable.run();
+        } catch (Exception e) {
+          e.printStackTrace();
+        }
+      }
+    }
+  }
+}