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Java > Open Source Codes > org > exolab > jms > messagemgr > MessageHandleComparator


1 /**
2  * Redistribution and use of this software and associated documentation
3  * ("Software"), with or without modification, are permitted provided
4  * that the following conditions are met:
5  *
6  * 1. Redistributions of source code must retain copyright
7  * statements and notices. Redistributions must also contain a
8  * copy of this document.
9  *
10  * 2. Redistributions in binary form must reproduce the
11  * above copyright notice, this list of conditions and the
12  * following disclaimer in the documentation and/or other
13  * materials provided with the distribution.
14  *
15  * 3. The name "Exolab" must not be used to endorse or promote
16  * products derived from this Software without prior written
17  * permission of Exoffice Technologies. For written permission,
18  * please contact info@exolab.org.
19  *
20  * 4. Products derived from this Software may not be called "Exolab"
21  * nor may "Exolab" appear in their names without prior written
22  * permission of Exoffice Technologies. Exolab is a registered
23  * trademark of Exoffice Technologies.
24  *
25  * 5. Due credit should be given to the Exolab Project
26  * (http://www.exolab.org/).
27  *
28  * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29  * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30  * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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37  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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39  * OF THE POSSIBILITY OF SUCH DAMAGE.
40  *
41  * Copyright 2000-2005 (C) Exoffice Technologies Inc. All Rights Reserved.
42  */
43 package org.exolab.jms.messagemgr;
44
45
46 import java.util.Comparator JavaDoc;
47
48
49 /**
50  * MessageHandleComparator is used to order messages on priority, acceptance
51  * time and sequence number.
52  *
53  * @version $Revision: 1.2 $ $Date: 2005/03/18 03:58:39 $
54  * @author <a HREF="mailto:jimm@intalio.com">Jim Mourikis</a>
55  */
56 public class MessageHandleComparator
57     implements Comparator JavaDoc {
58
59     // implementation of Comparator.compare
60 public int compare(Object JavaDoc o1, Object JavaDoc o2) {
61
62         int result = -1;
63
64         // The order is on priority-acceptance time-sequence number
65 if ((o1 instanceof MessageHandle) &&
66             (o2 instanceof MessageHandle)) {
67             MessageHandle m1 = (MessageHandle) o1;
68             MessageHandle m2 = (MessageHandle) o2;
69
70             if (m1.getPriority() == m2.getPriority()) {
71                 if (m1.getAcceptedTime() == m2.getAcceptedTime()) {
72                     if (m1.getSequenceNumber() == m2.getSequenceNumber()) {
73                         result = 0;
74                     } else if (m1.getSequenceNumber() > m2.getSequenceNumber()) {
75                         result = 1;
76                     } else {
77                         result = -1;
78                     }
79                 } else if (m1.getAcceptedTime() > m2.getAcceptedTime()) {
80                     result = 1;
81                 } else {
82                     result = -1;
83                 }
84             } else if (m1.getPriority() > m2.getPriority()) {
85                 result = -1;
86             } else {
87                 result = 1;
88             }
89         }
90
91         return result;
92     }
93
94     // implementation of Comparator.equals
95 public boolean equals(Object JavaDoc obj) {
96
97         if (obj instanceof MessageHandleComparator) {
98             return true;
99         } else {
100             return false;
101         }
102     }
103 }
104
105
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