public static Long nonNegative(@Nullable String role, Long x) {
		if (x.longValue() < 0) {
			throw new IllegalArgumentException(role + " (" + x + ") must be >= 0");
		}
		return x;
	}
public static Long nonNegative ( @ Nullable String role , Long x ) { if ( x . longValue ( ) < 0 ) { throw new IllegalArgumentException ( role + " (" + x + ") must be >= 0" ) ; } return x ; }
校验为非负数则返回该数字，否则抛出异常.