-final class IpUtil extends AbstractIetfInetUtil<IpClass, IpClass, IpClass, IpClass, IpClass> {
+import java.util.regex.Pattern;
+import javax.annotation.RegEx;
+
+final class IpUtil extends AbstractIetfInetUtil<IpClass, IpClass, IpClass, IpClass, IpClass, IpClass, IpClass, IpClass,
+ IpClass> {
+
+ @RegEx
+ private static final String IP_V4_REGEX = "^\\d+\\.\\d+\\.\\d+\\.\\d+$";
+ private static final Pattern IP_V4_PATTERN = Pattern.compile(IP_V4_REGEX);
+