histogram.hpp revision 1472:c18cbe5936b8 
1/*
2 * Copyright (c) 1998, 2000, 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// This class provides a framework for collecting various statistics.
26// The current implementation is oriented towards counting invocations
27// of various types, but that can be easily changed.
28//
29// To use it, you need to declare a Histogram*, and a subtype of
30// HistogramElement:
31//
32//  HistogramElement* MyHistogram;
33//
34//  class MyHistogramElement : public HistogramElement {
35//    public:
36//      MyHistogramElement(char* name);
37//  };
38//
39//  MyHistogramElement::MyHistogramElement(char* elementName) {
40//    _name = elementName;
41//
42//    if(MyHistogram == NULL)
43//      MyHistogram = new Histogram("My Call Counts",100);
44//
45//    MyHistogram->add_element(this);
46//  }
47//
48//  #define MyCountWrapper(arg) static MyHistogramElement* e = new MyHistogramElement(arg); e->increment_count()
49//
50// This gives you a simple way to count invocations of specfic functions:
51//
52// void a_function_that_is_being_counted() {
53//   MyCountWrapper("FunctionName");
54//   ...
55// }
56//
57// To print the results, invoke print() on your Histogram*.
58
59#ifdef ASSERT
60
61class HistogramElement : public CHeapObj {
62 protected:
63  jint _count;
64  const char* _name;
65
66 public:
67  HistogramElement();
68  virtual int count();
69  virtual const char* name();
70  virtual void increment_count();
71  void print_on(outputStream* st) const;
72  virtual int compare(HistogramElement* e1,HistogramElement* e2);
73};
74
75class Histogram : public CHeapObj {
76 protected:
77  GrowableArray<HistogramElement*>* _elements;
78  GrowableArray<HistogramElement*>* elements() { return _elements; }
79  const char* _title;
80  const char* title() { return _title; }
81  static int sort_helper(HistogramElement** e1,HistogramElement** e2);
82  virtual void print_header(outputStream* st);
83  virtual void print_elements(outputStream* st);
84
85 public:
86  Histogram(const char* title,int estimatedSize);
87  virtual void add_element(HistogramElement* element);
88  void print_on(outputStream* st) const;
89};
90
91#endif
92