/** Map of PostDateCache by workspace, site and sitemap/language. */
 protected Map<String, Map<String, Map<String, PostDateCache>>> _postsByDate;
 
 /** Map of PostTagCache by workspace, site and sitemap/language. */
 protected Map<String, Map<String, Map<String, PostTagCache>>> _postsByTag;
 
 /** Map of PostDateCache by workspace, site and sitemap/language. */
 protected Map<String, Map<String, Map<String, AllPostCache>>> _allPosts;
 
 /** Map of FuturePostCache by workspace, site and sitemap/language. */
 protected Map<String, Map<String, Map<String, FuturePostCache>>> _futurePostsCache;
 
 /** Caches are initialized by workspace, site and sitemap/language. */
 protected Map<String, Map<String, Map<String, Boolean>>> _initialized;
 
 /** Future caches are updated by workspace, site and sitemap/language. */
 protected Map<String, Map<String, Map<String, Date>>> _lastUpdateFuturePosts;