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Java > Open Source Codes > org > mr > core > stats > TemporalCounter


1 /*
2  * Copyright 2002 by
3  * <a HREF="http://www.coridan.com">Coridan</a>
4  * <a HREF="mailto: support@coridan.com ">support@coridan.com</a>
5  *
6  * The contents of this file are subject to the Mozilla Public License Version
7  * 1.1 (the "License"); you may not use this file except in compliance with the
8  * License. You may obtain a copy of the License at
9  * http://www.mozilla.org/MPL/
10  *
11  * Software distributed under the License is distributed on an "AS IS" basis,
12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13  * for the specific language governing rights and limitations under the
14  * License.
15  *
16  * The Original Code is "MantaRay" (TM).
17  *
18  * The Initial Developer of the Original Code is Uri Schneider.
19  * Portions created by the Initial Developer are Copyright (C) 2006
20  * Coridan Inc. All Rights Reserved.
21  *
22  * Contributor(s): all the names of the contributors are added in the source
23  * code where applicable.
24  *
25  * Alternatively, the contents of this file may be used under the terms of the
26  * LGPL license (the "GNU LESSER GENERAL PUBLIC LICENSE"), in which case the
27  * provisions of LGPL are applicable instead of those above. If you wish to
28  * allow use of your version of this file only under the terms of the LGPL
29  * License and not to allow others to use your version of this file under
30  * the MPL, indicate your decision by deleting the provisions above and
31  * replace them with the notice and other provisions required by the LGPL.
32  * If you do not delete the provisions above, a recipient may use your version
33  * of this file under either the MPL or the GNU LESSER GENERAL PUBLIC LICENSE.
34  
35  *
36  * This library is free software; you can redistribute it and/or modify it
37  * under the terms of the MPL as stated above or under the terms of the GNU
38  * Lesser General Public License as published by the Free Software Foundation;
39  * either version 2.1 of the License, or any later version.
40  *
41  * This library is distributed in the hope that it will be useful, but WITHOUT
42  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
43  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
44  * License for more details.
45  */

46 package org.mr.core.stats;
47
48 import org.mr.core.util.SystemTime;
49
50 /**
51  * Accessary class, used by StatManager.
52  *
53  * Created: Tue Jul 06 16:25:23 2004
54  *
55  * @author Uri Schneider
56  * @version 1.0
57  */

58 public class TemporalCounter {
59     private long[] slots;
60     private long earliest;
61     private int startMark;
62     private long slotSizeMilli;
63
64     public TemporalCounter(long slotSizeMilli, int slotCount) {
65         this.slots = new long[slotCount];
66         this.slotSizeMilli = slotSizeMilli;
67         this.earliest = SystemTime.currentTimeMillis() / slotSizeMilli;
68         this.startMark = 0;
69     } // TemporalCounter constructor
70

71     public synchronized void addSample(long sample) {
72         long current = SystemTime.currentTimeMillis() / slotSizeMilli;
73         if ((int) (current - this.earliest) >= this.slots.length) {
74             int difference =
75                 (int) (current - this.earliest) - this.slots.length + 1;
76             this.earliest += (long) difference;
77             if (difference > this.slots.length) {
78                 difference = this.slots.length;
79             }
80             for (int i = 0; i < difference; i++) {
81                 int slot = (this.startMark + i) % this.slots.length;
82                 this.slots[slot] = 0;
83             }
84             this.startMark = (this.startMark + difference) % this.slots.length;
85         }
86         int index = (this.startMark + ((int) (current - this.earliest))) %
87             this.slots.length;
88         this.slots[index] += sample;
89     }
90
91     public synchronized long getValue() {
92         // to synchronize the counter
93
addSample((long) 0);
94         long value = 0;
95         for (int i = 0; i < this.slots.length; i++) {
96             value += this.slots[i];
97         }
98
99         return value;
100     }
101 } // TemporalCounter
102
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