TimeMeasure


1   /*
2    * $Id: TimeMeasure.java,v 1.4 2004/12/01 07:54:30 hengels Exp $
3    * Copyright 2000,2005 wingS development team.
4    *
5    * This file is part of wingS (http://www.j-wings.org).
6    *
7    * wingS is free software; you can redistribute it and/or modify
8    * it under the terms of the GNU Lesser General Public License
9    * as published by the Free Software Foundation; either version 2.1
10   * of the License, or (at your option) any later version.
11   *
12   * Please see COPYING for the complete licence.
13   */
14  package org.wings.util;
15  
16  import java.text.MessageFormat  ;
17  import java.util.ArrayList  ;
18  import java.util.Iterator  ;
19  
20  /*
21   * Ein Klasse, die Zeitmessungen aufnimmt und diese in Relation zueineander
22   * setzt. Zum Start der Zeitmessung Methode start kurzer Beschreibung was
23   * gemessen wird als Parameter aufrufen. Das Ende der Zeitmessung wird durch
24   * stop angezeigt. Es kann nur eine Zeitmessung gleichzeitig stattfinden. Die
25   * Ausgabe ist nicht sortiert, gibt aber die relativen Unterschiede in der
26   * Dauer der einzelnen Messungen an. Die Messung mit der laengsten Dauer ist
27   * der Referenzwert (1.0).
28   */
29  
30  /**
31   * Some simple stop watch. It allows to measure multiple time periods
32   * and prints them. Usage: call start(comment) and stop() for
33   * each period of time.
34   *
35   * @author <a HREF="mailto:haaf@mercatis.de">Armin Haaf</a>
36   * @version $Revision: 1.4 $
37   */
38  public class TimeMeasure {
39      protected final static double RESOLUTION = 100.0;
40  
41      /**
42       * List of measurements.
43       */
44      protected final ArrayList   measures;
45  
46      /**
47       * Message formatter
48       */
49      protected final MessageFormat   formatter;
50  
51      /**
52       * the current time measurement.
53       */
54      protected Measure current;
55  
56      /**
57       * Simple TimeMesaure with default format.
58       */
59      public TimeMeasure() {
60          this(new MessageFormat  ("{0}\t: {1}\t {2}x\n"));
61      }
62  
63      /**
64       * A new TimeMeasure which reports in a specific format. The
65       * format is a standard MessageFormat with the following variables:
66       * <ul>
67       * <li><code>{0}</code> the measurement comment</li>
68       * <li><code>{1}</code> the time it took</li>
69       * <li><code>{2}</code> how many times this is faster than the
70       * slowest measurement</li>
71       * </ul>
72       */
73      public TimeMeasure(MessageFormat   formatter) {
74          this.measures = new ArrayList  ();
75          this.formatter = formatter;
76      }
77  
78      /**
79       * Reset of all Measurements.
80       */
81      public void reset() {
82          measures.clear();
83      }
84  
85      /*
86       * Startet eine neue Messsung.
87       * @param comment  Die Beschreibung der Messung.
88       */
89      public void start(String   comment) {
90          current = new Measure(comment);
91      }
92  
93      /*
94       * Startet eine neue Messsung.
95       * @param comment  Die Beschreibung der Messung.
96      public Object generate(String comment) {
97          current = new Measure();
98          actual.comment = comment;
99          measures.add(actual);
100         return actual;
101     }
102      */
103 
104     /*
105      * Addiert eine Messsung zu einer bestehenden.
106      * @param comment  Die Beschreibung der Messung.
107     public void addToMeasure(Object measure) {
108         int index = measures.indexOf(measure);
109         if ( index<0 ) {
110             System.err.println("Measure does not exists " + measure);
111             actual = null;
112             return;
113         }
114 
115         actual = (Measure)measures.get(index);
116         measures.remove(index);
117 
118         actual.start = System.currentTimeMillis();
119     }
120      */
121 
122     /**
123      * stop current time measurement and store it.
124      */
125     public void stop() {
126         if (current != null) {
127             current.stop();
128             measures.add(current);
129             current = null;
130         }
131     }
132 
133     /**
134      * determines the time duration of the longest or shortest time interval.
135      *
136      * @param findShortest boolean 'true', if we are looking for the shortest
137      *                     time interval; 'false' if we are looking for the
138      *                     longest.
139      */
140     private long findReferenceValue(boolean findShortest) {
141         long result = findShortest ? Long.MAX_VALUE : -1;
142 
143         Iterator   it = measures.iterator();
144         while (it.hasNext()) {
145             Measure m = (Measure) it.next();
146             result = (findShortest
147                     ? Math.min(result, m.getDuration())
148                     : Math.max(result, m.getDuration()));
149         }
150         return result;
151     }
152 
153     public String   print() {
154         return print(false);
155     }
156 
157     /**
158      * creates a formatted output (using the MessageFormat) of all
159      * results. The output is sorted in the in the sequence the time
160      * measurements took place.
161      * Writes the relative time to either the shortest or the longest
162      * time interval.
163      *
164      * @param shortestIsReference boolean true, if the shortest time interval
165      *                            is the reference value (1.0). False, if the
166      *                            longest is the reference.
167      */
168     public String   print(boolean shortestIsReference) {
169         StringBuffer   result = new StringBuffer  ();
170         long reference = findReferenceValue(shortestIsReference);
171         Iterator   it = measures.iterator();
172         while (it.hasNext()) {
173             Measure m = (Measure) it.next();
174             String   factor = " -- ";
175             long duration = m.getDuration();
176             if (reference > 0) {
177                 long tmp = (long) ((duration * RESOLUTION) / reference);
178                 factor = String.valueOf(tmp / RESOLUTION);
179             }
180             Object  [] args = {m.getComment(), (duration + "ms"), factor};
181             result.append(formatter.format(args));
182         }
183         return result.toString();
184     }
185 
186     public String   toString() {
187         return print();
188     }
189 
190     /**
191      * A class to store one period of time.
192      */
193     private final static class Measure {
194         /**
195          * start time.
196          */
197         private final long start;
198 
199         /**
200          * stop time.
201          */
202         private long stop;
203 
204         /**
205          * Die Gesamtdauer der Messung
206          */
207         private long duration;
208 
209         /**
210          * Description.
211          */
212         private String   comment;
213 
214         public Measure(String   comment) {
215             start = System.currentTimeMillis();
216             this.comment = comment;
217         }
218 
219         public void stop() {
220             stop = System.currentTimeMillis();
221             duration = stop - start;
222         }
223 
224         public long getDuration() { return duration; }
225 
226         public String   getComment() { return comment; }
227     }
228 }
229 
230 
231
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