--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/ProgressiveHeapVisitor.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2000, 2006, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+package sun.jvm.hotspot.utilities;
+
+import sun.jvm.hotspot.memory.*;
+import sun.jvm.hotspot.oops.*;
+
+/** This class wraps a user's chosen HeapVisitor with the
+    functionality that a chosen "thunk" is called periodically during
+    the heap traversal. This allows a progress bar to be displayed
+    during long heap scans. */
+
+public class ProgressiveHeapVisitor implements HeapVisitor {
+  private HeapVisitor userHeapVisitor;
+  private HeapProgressThunk thunk;
+  private long usedSize;
+  private long visitedSize;
+  private double lastNotificationFraction;
+  private static double MINIMUM_NOTIFICATION_FRACTION = 0.01;
+
+  public ProgressiveHeapVisitor(HeapVisitor userHeapVisitor,
+                                HeapProgressThunk thunk) {
+    this.userHeapVisitor = userHeapVisitor;
+    this.thunk = thunk;
+  }
+
+  public void prologue(long usedSize) {
+    this.usedSize = usedSize;
+    visitedSize = 0;
+    userHeapVisitor.prologue(usedSize);
+  }
+
+  public boolean doObj(Oop obj) {
+    userHeapVisitor.doObj(obj);
+    visitedSize += obj.getObjectSize();
+    double curFrac = (double) visitedSize / (double) usedSize;
+    if (curFrac > lastNotificationFraction + MINIMUM_NOTIFICATION_FRACTION) {
+      thunk.heapIterationFractionUpdate(curFrac);
+      lastNotificationFraction = curFrac;
+    }
+    return false;
+  }
+
+  public void epilogue() {
+    userHeapVisitor.epilogue();
+    thunk.heapIterationComplete();
+  }
+}