1 /*
   2  * Copyright (c) 2002, 2005, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.tools;
  26 
  27 import sun.jvm.hotspot.debugger.*;
  28 import sun.jvm.hotspot.oops.*;
  29 import sun.jvm.hotspot.runtime.*;
  30 import java.io.PrintStream;
  31 
  32 /** A sample tool which uses the Serviceability Agent's APIs to obtain
  33     an object histogram from a remote or crashed VM. */
  34 public class ObjectHistogram extends Tool {
  35 
  36     public ObjectHistogram() {
  37        super();
  38     }
  39 
  40     public ObjectHistogram(JVMDebugger d) {
  41        super(d);
  42     }
  43 
  44    public void run() {
  45       run(System.out, System.err);
  46    }
  47 
  48    public void run(PrintStream out, PrintStream err) {
  49       // Ready to go with the database...
  50       ObjectHeap heap = VM.getVM().getObjectHeap();
  51       sun.jvm.hotspot.oops.ObjectHistogram histogram =
  52         new sun.jvm.hotspot.oops.ObjectHistogram();
  53       err.println("Iterating over heap. This may take a while...");
  54       long startTime = System.currentTimeMillis();
  55       heap.iterate(histogram);
  56       long endTime = System.currentTimeMillis();
  57       histogram.printOn(out);
  58       float secs = (float) (endTime - startTime) / 1000.0f;
  59       err.println("Heap traversal took " + secs + " seconds.");
  60    }
  61 
  62    public static void main(String[] args) {
  63       ObjectHistogram oh = new ObjectHistogram();
  64       oh.start(args);
  65       oh.stop();
  66    }
  67 }