在JAXP中透明的缓存XSL转换器

在JAXP中透明的缓存XSL转换器(4)     throws TransformerConfigurationException
  {
    // Search the cache for the templates entry
    TemplatesCacheEntry templatesCacheEntry = read(file.getAbsolutePath());

    // If entry is found
    if (templatesCacheEntry != null)
    {
      // Check timestamp of modification
      if (templatesCacheEntry.lastModified
        < templatesCacheEntry.templatesFile.lastModified())
        // Clear entry, if it is obsolete
        templatesCacheEntry = null;
    }
    // If no templatesEntry is found or this entry was obsolete
    if (templatesCacheEntry == null)
    {
      logger.debug("Loading transformation [" + file.getAbsolutePath() + "].");
      // If this file does not exists, throw the exception
      if (!file.exists())
      {
        throw new TransformerConfigurationException(
          "Requested transformation ["
          + file.getAbsolutePath()
          + "] does not exist.");
      }

      // Create new cache entry
      templatesCacheEntry =
        new TemplatesCacheEntry(newTemplates(new StreamSource(file)), file);

      // Save this entry to the cache