Stats


1   /**
2    * C-JDBC: Clustered JDBC.
3    * Copyright (C) 2002-2004 French National Institute For Research In Computer
4    * Science And Control (INRIA).
5    * Contact: c-jdbc@objectweb.org
6    * 
7    * This library is free software; you can redistribute it and/or modify it
8    * under the terms of the GNU Lesser General Public License as published by the
9    * Free Software Foundation; either version 2.1 of the License, or any later
10   * version.
11   * 
12   * This library is distributed in the hope that it will be useful, but WITHOUT
13   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14   * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
15   * for more details.
16   * 
17   * You should have received a copy of the GNU Lesser General Public License
18   * along with this library; if not, write to the Free Software Foundation,
19   * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
20   *
21   * Initial developer(s): Emmanuel Cecchet.
22   * Contributor(s): Julie Marguerite, Sara Bouchenak.
23   */
24  
25  package org.objectweb.cjdbc.common.util;
26  
27  /**
28   * This class provides thread-safe statistics. Each statistic entry is composed
29   * as follow:
30   * <ul>
31   * <li>count: statistic counter</li>
32   * <li>error: statistic error counter</li>
33   * <li>minTime: minimum time for this entry (automatically computed)</li>
34   * <li>maxTime: maximum time for this entry (automatically computed)</li>
35   * <li>totalTime: total time for this entry</li>
36   * </ul>
37   * 
38   * @author <a HREF="mailto:Emmanuel.Cecchet@inria.fr">Emmanuel Cecchet </a>
39   * @author <a HREF="mailto:julie.marguerite@inria.fr">Julie Marguerite </a>
40   * @version 1.0
41   */
42  
43  public class Stats
44  {
45    /** Statistic counter */
46    private int    count;
47  
48    /** Statistic error counter */
49    private int    error;
50  
51    /** Cache hits counter */
52    private int    cacheHit;
53  
54    /** Minimum time for this entry (automatically computed) */
55    private long   minTime;
56  
57    /** Maximum time for this entry (automatically computed) */
58    private long   maxTime;
59  
60    /** Total time for this entry */
61    private long   totalTime;
62  
63    /** Name of the stats. */
64    private String   name;
65  
66    /**
67     * Creates a new <code>Stats</code> instance. The entries are reset to 0.
68     * 
69     * @param statName The stat name
70     */
71    public Stats(String   statName)
72    {
73      name = statName;
74      reset();
75    }
76  
77    /**
78     * Resets all entries to 0.
79     */
80    public synchronized void reset()
81    {
82      count = 0;
83      error = 0;
84      minTime = Long.MAX_VALUE;
85      maxTime = Long.MIN_VALUE;
86      totalTime = 0;
87    }
88  
89    /**
90     * Increments an entry count by one.
91     */
92    public synchronized void incrementCount()
93    {
94      count++;
95    }
96  
97    /**
98     * Increments an entry error by one.
99     */
100   public synchronized void incrementError()
101   {
102     error++;
103   }
104 
105   /**
106    * Increments an entry cache hit by one.
107    */
108   public synchronized void incrementCacheHit()
109   {
110     cacheHit++;
111   }
112 
113   /**
114    * Adds a new time sample for this entry. <code>time</code> is added to
115    * total time and both minTime and maxTime are updated if needed.
116    * 
117    * @param time time to add to this entry
118    */
119   public synchronized void updateTime(long time)
120   {
121     if (time < 0)
122     {
123       System.err.println("Negative time received in Stats.updateTime(" + time
124           + ")\n");
125       return;
126     }
127     totalTime += time;
128     if (time > maxTime)
129       maxTime = time;
130     if (time < minTime)
131       minTime = time;
132   }
133 
134   /**
135    * Gets the name of the current stat.
136    * 
137    * @return stat name
138    */
139   public String   getName()
140   {
141     return name;
142   }
143 
144   /**
145    * Gets current count of an entry.
146    * 
147    * @return current entry count value
148    */
149   public synchronized int getCount()
150   {
151     return count;
152   }
153 
154   /**
155    * Gets current error count of an entry
156    * 
157    * @return current entry error value
158    */
159   public synchronized int getError()
160   {
161     return error;
162   }
163 
164   /**
165    * Gets current cache hit count of an entry
166    * 
167    * @return current entry cache hit value
168    */
169   public synchronized int getCacheHit()
170   {
171     return cacheHit;
172   }
173 
174   /**
175    * Gets the minimum time of an entry
176    * 
177    * @return entry minimum time
178    */
179   public synchronized long getMinTime()
180   {
181     return minTime;
182   }
183 
184   /**
185    * Gets the maximum time of an entry
186    * 
187    * @return entry maximum time
188    */
189   public synchronized long getMaxTime()
190   {
191     return maxTime;
192   }
193 
194   /**
195    * Gets the total time of an entry
196    * 
197    * @return entry total time
198    */
199   public synchronized long getTotalTime()
200   {
201     return totalTime;
202   }
203 
204   /**
205    * Adds the entries of another <code>Stats</code> object to this one.
206    * 
207    * @param anotherStat stat to merge with current stat
208    * @throws Exception if you try to merge a stat with itself
209    */
210   public synchronized void merge(Stats anotherStat) throws Exception  
211   {
212     if (this == anotherStat)
213     {
214       throw new Exception  ("You cannot merge a stat with itself");
215     }
216 
217     count += anotherStat.getCount();
218     error += anotherStat.getError();
219     cacheHit += anotherStat.getCacheHit();
220     if (minTime > anotherStat.getMinTime())
221       minTime = anotherStat.getMinTime();
222     if (maxTime < anotherStat.getMaxTime())
223       maxTime = anotherStat.getMaxTime();
224     totalTime += anotherStat.getTotalTime();
225   }
226 
227   /**
228    * Displays the statistics on the standard output.
229    */
230   public void displayOnStdout()
231   {
232     System.out.println(multipleLineDisplay());
233   }
234 
235   /**
236    * Displays the statistics information on multiple lines.
237    * 
238    * @return a <code>String</code> containing the Stat output
239    */
240   public String   multipleLineDisplay()
241   {
242     String   output = name + " statistics:\n" + "  Count: " + count + "\n"
243         + "  Error: " + error + "\n";
244     if (totalTime != 0)
245     {
246       output += "  Min time: " + minTime + " ms\n";
247       output += "  Max time: " + maxTime + " ms\n";
248     }
249     else
250     {
251       output += "  Min time: 0 ms\n";
252       output += "  Max time: 0 ms\n";
253     }
254     if (count == 0)
255       output += "  Avg time: 0 ms\n";
256     else
257       output += "  Avg time: " + totalTime / count + " ms\n";
258     output += "  Tot time: " + totalTime + " ms\n";
259 
260     double timeSec = totalTime / 1000;
261     double timeMin = timeSec / 60, throup;
262     throup = (timeMin != 0) ? (count / timeMin) : (count / timeSec);
263     output += "  Throughput: " + throup
264         + ((timeMin != 0) ? " requests/minute" : " requests/second");
265     return output;
266   }
267 
268   /**
269    * Displays the statistics information on a single line in the format: name
270    * count error cacheHit %hit minTime maxTime avgTime totalTime
271    * 
272    * @return a <code>String</code> containing the Stat output
273    */
274   public String   singleLineDisplay()
275   {
276     String   output = name + " " + count + " " + error + " " + cacheHit + " ";
277     if (count == 0)
278       output += "0 ";
279     else
280       output += ((double) cacheHit / (double) count * 100.0) + " ";
281     if (totalTime != 0)
282       output += minTime + " " + maxTime + " ";
283     else
284       output += " 0 0 ";
285     if (count == 0)
286       output += "0 ";
287     else
288       output += totalTime / count + " ";
289     output += totalTime;
290     double timeSec = totalTime / 1000;
291     double timeMin = timeSec / 60, throup;
292     throup = (timeMin != 0) ? (count / timeMin) : (count / timeSec);
293     output += throup
294         + ((timeMin != 0) ? " requests/minute" : " requests/second");
295     return output;
296   }
297 
298   /**
299    * Get the stat information in the form of a String table. Format is: name
300    * count error cacheHit %hit minTime maxTime avgTime totalTime
301    * 
302    * @return the String table corresponding to this stat
303    */
304   public String  [] toStringTable()
305   {
306     String  [] foo = {
307         name,
308         Integer.toString(count),
309         Integer.toString(error),
310         Integer.toString(cacheHit),
311         (count == 0) ? "0" : Float.toString((float) cacheHit / (float) count
312             * (float) 100.0), Long.toString(minTime), Long.toString(maxTime),
313         (count == 0) ? "0" : Float.toString((float) totalTime / (float) count),
314         Long.toString(totalTime)};
315     return foo;
316   }
317 }
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