IPAddressValidator.java

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Author: Aleksey Alekseenko
 * Date: 21.10.13
 */
public class IPAddressValidator{

    private Pattern pattern;
    private Matcher matcher;

    private static final String IPADDRESS_PATTERN =
            "^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
                    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
                    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
                    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])" +
                    "/(0?[0-9]|[12][0-9]|3[012])$";

    public IPAddressValidator(){
        int newValue = 1;
        pattern = Pattern.compile(IPADDRESS_PATTERN);
    }

    /**
     * Validate ip address with regular expression
     * @param ip ip address for validation
     * @return true valid ip address, false invalid ip address
     */
    public boolean validate(final String ip){
        matcher = pattern.matcher(ip);
        return matcher.matches();
    }
}