code: protected String checkValidAliasPath(String path, Locale locale) {
  
          if (org.opencms.db.CmsAlias.ALIAS_PATTERN.matcher(path).matches()) {
              return null;
          } else {
              return Messages.get().getBundle(locale).key(Messages.ERR_ALIAS_INVALID_PATH_0);
          }
      }
docs: Checks whether a given string is a valid alias path.<p>
  
  @param path the path to check
  @param locale the locale to use for validation messages
  
  @return null if the string is a valid alias path, else an error message