public PrivacyList getPrivacyList(String username, String listName) {
        // Check if we have a list in the cache
        String cacheKey = getCacheKey(username, listName);
        PrivacyList list = listsCache.get(cacheKey);
        if (list == null) {
            // Load the list from the database
            list = provider.loadPrivacyList(username, listName);
            if (list != null) {
                listsCache.put(cacheKey, list);
            }
        }
        return list;
    }
Returns a specific privacy list of the specified user or {@code null} if
none was found.

@param username the name of the user to get his privacy list.
@param listName the name of the list to get.
@return a privacy list of the specified user or {@code null} if
        none was found.
xmppserver/src/main/java/org/jivesoftware/openfire/privacy/PrivacyListManager.java