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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
31   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
32   * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39   * OF THE POSSIBILITY OF SUCH DAMAGE.
40   *
41   * Copyright 2005 (C) Exoffice Technologies Inc. All Rights Reserved.
42   *
43   * $Id: TimedCondition.java,v 1.1 2005/08/30 06:23:11 tanderson Exp $
44   */
45  package org.exolab.jms.messagemgr;
46  
47  
48  /***
49   * A timed {@link Condition}.
50   *
51   * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
52   * @version $Revision: 1.1 $ $Date: 2005/08/30 06:23:11 $
53   */
54  public class TimedCondition implements Condition {
55  
56      /***
57       * The absolute time, in millseconds.
58       */
59      private final long _time;
60  
61      /***
62       * Determines if the condition evaluates <code>true</code> while before or
63       * after <code>time</code>.
64       */
65      private final boolean _before;
66  
67  
68      /***
69       * Construct a new <code>TimedCondition</code>.
70       *
71       * @param time   the absolute time, in milliseconds
72       * @param before determines if the condition evaluates <code>true</code>
73       *               while before or after <code>time</code>.
74       */
75      private TimedCondition(long time, boolean before) {
76          _time = time;
77          _before = before;
78      }
79  
80      /***
81       * Evaluates the condition.
82       *
83       * @return the value of the condition
84       */
85      public boolean get() {
86          final long current = System.currentTimeMillis();
87          if (_before) {
88              return current < _time;
89          }
90          return current >= _time;
91      }
92  
93      /***
94       * Create a new <code>TimedCondition</code> that evaluates <code>true</code>
95       * while the current time &lt; Now + time
96       *
97       * @param time the relative time, in milliseconds
98       * @return a condition that evaluates <code>true</code> while the current
99       * time &lt; Now + time
100      */
101     public static Condition before(long time) {
102         return new TimedCondition(getAbsTime(time), true);
103     }
104 
105     /***
106      * Create a new <code>TimedCondition</code> that evaluates <code>true</code>
107      * while the current time &gt;= Now + time
108      *
109      * @param time the relative time, in milliseconds
110      * @return a condition that evaluates <code>true</code> while the current
111      * time &gt;= Now + time
112      */
113     public static Condition after(long time) {
114         return new TimedCondition(getAbsTime(time), false);
115     }
116 
117     /***
118      * Helper to return an absolute time in milliseconds, relative to now.
119      *
120      * @param time the relative time in milliseconds
121      * @return the absolute time
122      */
123     private static long getAbsTime(long time) {
124         return System.currentTimeMillis() + time;
125     }
126 }