SimpleDateFormatPool


1   /*****************************************
2    *                                       *
3    *  JBoss Portal: The OpenSource Portal  *
4    *                                       *
5    *       Forums JBoss Portlet            *
6    *                                       *
7    *   Distributable under GPL license.    *
8    *   See terms of license at gnu.org.    *
9    *                                       *
10   *****************************************/
11  package org.jboss.portlet.forums.helper;
12  
13  import java.text.DateFormat  ;
14  import java.text.SimpleDateFormat  ;
15  import java.util.Date  ;
16  
17  /**
18   * A simple date format pool. These objects are very expensive
19   * to create.
20   *
21   * @author <a HREF="mailto:julien@jboss.org">Julien Viet</a>
22   * @version $Revision: 1.1.1.1 $
23   */
24  public final class SimpleDateFormatPool
25     extends AbstractPool
26  {
27     /**
28      * The date version.
29      */
30     private int version = 0;
31  
32     /**
33      * Default value is same as "D M d, Y g:i a" in PHP.
34      */
35     private String   pattern = "EEE MMM d, yyyy HH:mm aaa";
36  
37     /**
38      * Creates a new {@link SimpleDateFormatPool} object.
39      *
40      * @param maxSize DOCUMENT_ME
41      * @param initialSize DOCUMENT_ME
42      */
43     public SimpleDateFormatPool(int maxSize,
44                                 int initialSize)
45     {
46        initialize(maxSize, initialSize);
47     }
48  
49     /**
50      * DOCUMENT_ME
51      *
52      * @param format DOCUMENT_ME
53      */
54     public void setPattern(String   format)
55     {
56        version++;
57        this.pattern = format;
58     }
59  
60     /**
61      * DOCUMENT_ME
62      *
63      * @return DOCUMENT_ME
64      */
65     public String   getPattern()
66     {
67        return pattern;
68     }
69  
70     /**
71      * DOCUMENT_ME
72      *
73      * @return DOCUMENT_ME
74      */
75     protected Object   _create()
76     {
77        return new SimpleDateFormatPool.VersionedSimpleDateFormat(pattern, version);
78     }
79  
80     /**
81      * DOCUMENT_ME
82      *
83      * @param instance DOCUMENT_ME
84      */
85     protected void _acquire(Object   instance)
86     {
87        SimpleDateFormatPool.VersionedSimpleDateFormat format =
88           (SimpleDateFormatPool.VersionedSimpleDateFormat) instance;
89        if (format.version < version)
90        {
91           format.version = version;
92           format.applyPattern(pattern);
93        }
94     }
95  
96     private static class VersionedSimpleDateFormat
97        extends SimpleDateFormat  
98     {
99        private int version;
100 
101       /**
102        * Creates a new {@link VersionedSimpleDateFormat} object.
103        *
104        * @param pattern DOCUMENT_ME
105        * @param version DOCUMENT_ME
106        */
107       public VersionedSimpleDateFormat(String   pattern,
108                                        int    version)
109       {
110          super(pattern);
111          this.version = version;
112       }
113    }
114 
115    /**
116     * DOCUMENT_ME
117     *
118     * @param date DOCUMENT_ME
119     *
120     * @return DOCUMENT_ME
121     */
122    public String   formatDate(Date   date)
123    {
124       DateFormat   format = null;
125       try
126       {
127          format = (DateFormat  ) acquire();
128          return format.format(date);
129       }
130       finally
131       {
132          release(format);
133       }
134    }
135 }
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