examples/arrayperformance.java

   1 //#region license
   2 // boo - an extensible programming language for the CLI
   3 // Copyright (C) 2004 Rodrigo Barreto de Oliveira
   4 //
   5 // This library is free software; you can redistribute it and/or
   6 // modify it under the terms of the GNU Lesser General Public
   7 // License as published by the Free Software Foundation; either
   8 // version 2.1 of the License, or (at your option) any later version.
   9 //
  10 // This library is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13 // Lesser General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU Lesser General Public
  16 // License along with this library; if not, write to the Free Software
  17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18 //
  19 // Contact Information
  20 //
  21 // mailto:rbo@acm.org
  22 //#endregion
  23
  24 import java.util.ArrayList;
  25 import java.util.Iterator;
  26
  27 class xrange implements Iterator
  28 {
  29         int _max;
  30         int _current;
  31
  32         public xrange(int max)
  33         {
  34                 _max = max;
  35                 _current = 0;
  36         }
  37
  38         public boolean hasNext()
  39         {
  40                 return _current < _max;
  41         }
  42
  43         public Object next()
  44         {
  45                 return new Integer(_current++);
  46         }
  47
  48         public void remove()
  49         {
  50         }
  51 }
  52
  53 public class arrayperformance
  54 {
  55         public static final int items = 2000000;
  56
  57         public static void main(String[] args)
  58         {
  59                 test();
  60                 test();
  61                 test();
  62         }
  63
  64         private static void test()
  65         {
  66                 Object[] array = new Object[items];
  67                 for (int i = 0; i < array.length; i++)
  68                 {
  69                         array[i] = new Object();
  70                 }
  71
  72                 ArrayList collect = new ArrayList();
  73
  74                 Iterator i = new xrange(items);
  75                 long start = System.currentTimeMillis();
  76                 while (i.hasNext())
  77                 {
  78                         int index = ((Integer)i.next()).intValue();
  79                         collect.add(array[index]);
  80                 }
  81                 System.out.println((System.currentTimeMillis() - start) + " elapsed.");
  82         }
  83 }
  84