code: private static void addSuffixIfAvailable(String messageBundlePath,
  			List<String> availableLocaleSuffixes, Locale locale,
  			String fileSuffix, GrailsServletContextResourceReader rsReader) {
  
  		String localMsgResourcePath = toBundleName(messageBundlePath, locale)
  				+ fileSuffix;
  
  		boolean isFileSystemResourcePath = rsReader
  				.isFileSystemPath(localMsgResourcePath);
  
  		boolean resourceFound = false;
  		String path = localMsgResourcePath;
  		if (!isFileSystemResourcePath) {
  			// Try to retrieve the resource from the servlet context (used in war mode)
  			path = WEB_INF_DIR + localMsgResourcePath;
  		}
  		InputStream is = null;
  		try{
  			is = rsReader.getResourceAsStream(path);
  			resourceFound =  is != null;
  		}finally{
  			IOUtils.close(is);
  		}
  		
  		if (resourceFound) {
  
  			String suffix = localMsgResourcePath.substring(messageBundlePath
  					.length());
  			if (suffix.length() > 0) {
  
  				if (suffix.length() == fileSuffix.length()) {
  					suffix = "";
  				} else {
  					// remove the "_" before the suffix "_en_US" => "en_US"
  					suffix = suffix.substring(1,
  							suffix.length() - fileSuffix.length());
  				}
  			}
  			availableLocaleSuffixes.add(suffix);
  		}
  	}
docs: Add the locale suffix if the message resource bundle file exists.
  
  @param messageBundlePath
  the message resource bundle path
  @param availableLocaleSuffixes
  the list of available locale suffix to update
  @param locale
  the locale to check.
  @param fileSuffix
  the file suffix
  @param rsReader
  the grails servlet context resource reader