ThemeCache


1   package org.roller.presentation.website;
2   
3   import org.roller.util.LRUCache2;
4   
5   /**
6    * Caches the Theme files to avoid repeated reading of the files from the
7    * harddrive.
8    * 
9    * @author llavandowska
10   */
11  public class ThemeCache
12  {
13      private static ThemeCache INSTANCE = new ThemeCache();
14      private static String   cacheName = "ThemeFiles";
15      /**
16       * How many objects to store in cache.
17       * @TODO Add configuration for maxObjects in theme cache
18       */
19      private static int  maxObjects = 500;
20      
21      private static LRUCache2 cache = new LRUCache2(maxObjects, 30 * 60 * 1000);
22      
23      /**
24       * How long until an object in cache expires.
25       * @TODO Add configuration for theme cache timeout
26       */
27      private long expireInterval = 1000l*60*60*24; // 1 second * 1 min * 1 hr * 24 hours
28      
29      /**
30       * Should the PreviewResourceLoader cache the Template files.
31       * @TODO Add configuration for enabling theme template caching
32       */
33      private static boolean cacheTemplateFiles = false;
34          
35      /** Private constructor to prevent outside instantiation **/
36      private ThemeCache() { }
37          
38      /**
39       * 
40       */
41      public static ThemeCache getInstance()
42      {
43          return INSTANCE;
44      }
45      
46      /**
47       * 
48       */
49      public String   putIntoCache(String   themeName, String   fileName, String   template)
50      {
51          if (cacheTemplateFiles)
52          {
53              cache.put(themeName+":"+fileName, template);
54          }
55          return template;
56  
57      }
58      
59      /**
60       * Null will be returned if there is a problem or if caching is "turned
61       * off".
62       */
63      public String   getFromCache(String   themeName, String   fileName)
64      {
65          if (!cacheTemplateFiles) return null;
66          return (String  ) cache.get(themeName + ":" + fileName);
67      }
68      
69      /**
70       * 
71       */
72      public void removeFromCache(String   themeName, String   fileName)
73      {
74          if (!cacheTemplateFiles) return;
75          cache.purge( new String  [] { themeName+":"+fileName } );
76      }
77  
78      
79      /**
80       * The list of files in a Theme is cached as a String[], the key being the
81       * Theme location itself.
82       * 
83       * @param themeDir
84       * @param fileNames
85       * @return String[]
86       */
87      public String  [] setFileList(String   themeDir, String  [] fileNames)
88      {
89          if (cacheTemplateFiles)
90          {
91                  cache.put(themeDir, fileNames);
92          }
93          return fileNames;
94  
95      }
96      
97      /**
98       * The list of files in a Theme is cached as a String[], the key being the
99       * Theme location itself.  If caching is turned off this will return null.
100      * 
101      * @param theme
102      * @return String[]
103      */
104     public String  [] getFileList(String   themeDir)
105     {
106         if (!cacheTemplateFiles) return null;
107         return (String  [])cache.get(themeDir);
108     }
109 }
110
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