--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/oops/ObjectHistogram.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2000-2005 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.oops;
+
+import java.io.*;
+import java.util.*;
+
+public class ObjectHistogram implements HeapVisitor {
+
+  public ObjectHistogram() { map = new HashMap(); }
+
+  private HashMap map;
+
+  public void prologue(long size) {}
+
+  public boolean doObj(Oop obj) {
+    Klass klass = obj.getKlass();
+    if (!map.containsKey(klass)) map.put(klass, new ObjectHistogramElement(klass));
+    ((ObjectHistogramElement) map.get(klass)).updateWith(obj);
+        return false;
+  }
+
+  public void epilogue() {}
+
+  /** Call this after the iteration is complete to obtain the
+      ObjectHistogramElements in descending order of total heap size
+      consumed in the form of a List<ObjectHistogramElement>. */
+  public List getElements() {
+    List list = new ArrayList();
+    list.addAll(map.values());
+    Collections.sort(list, new Comparator() {
+      public int compare(Object o1, Object o2) {
+        return ((ObjectHistogramElement) o1).compare((ObjectHistogramElement) o2);
+      }
+    });
+    return list;
+  }
+
+  public void print() { printOn(System.out); }
+
+  public void printOn(PrintStream tty) {
+    List list = getElements();
+    ObjectHistogramElement.titleOn(tty);
+    Iterator iterator = list.listIterator();
+    while (iterator.hasNext()) {
+      ((ObjectHistogramElement) iterator.next()).printOn(tty);
+    }
+  }
+}