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 
  61 class 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 
  75 class 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