ObjectHistogram.java

/*
 * Copyright (c) 2000, 2008, 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.
 *
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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();
    int num=0;
    int totalCount=0;
    int totalSize=0;
    while (iterator.hasNext()) {
      ObjectHistogramElement el = (ObjectHistogramElement) iterator.next();
      num++;
      totalCount+=el.getCount();
      totalSize+=el.getSize();
      tty.print(num + ":" + "\t\t");
      el.printOn(tty);
    }
    tty.println("Total : " + "\t" + totalCount + "\t" + totalSize);
  }
}