gistfile1.java

        public FormValidation doCheckOsVersion(@QueryParameter String value) {
            return doCheckOsVersion(value, true).getFormValidation();
        }

        private ValidationResult doCheckOsVersion(String osVersion, boolean allowVariables) {
            if (osVersion == null || osVersion.equals("")) {
                return ValidationResult.error(Messages.OS_VERSION_REQUIRED());
            }
            if (!allowVariables && osVersion.matches(Constants.REGEX_VARIABLE)) {
                return ValidationResult.error(Messages.INVALID_OS_VERSION());
            }

            return ValidationResult.ok();
        }