code: public static final String id(String id) {
  		if (StringUtils.startsWith(id, PREFIX)) {
  			return PREFIX.concat(Utils.noSpaces(Utils.stripAndTrim(id.replaceAll(PREFIX, ""), " "), "-"));
  		} else if (id != null) {
  			return PREFIX.concat(Utils.noSpaces(Utils.stripAndTrim(id, " "), "-"));
  		} else {
  			return null;
  		}
  	}
docs: Returns the correct id of this app with prefix.
  @param id an id like "myapp"
  @return the full id, e.g. "app:myapp"