Java Regex.java

/*
Write a class called myRegex which will contain a string pattern. You need to write a regular expression and assign it to the pattern such that it can be used to validate an IP address. Use the following definition of an IP address:
IP address is a string in the form "A.B.C.D", where the value of A, B, C, and D may range from 0 to 255. Leading zeros are allowed. The length of A, B, C, or D can't be greater than 3.
Some valid IP address:
000.12.12.034
121.234.12.12
23.45.12.56
Some invalid IP address:
000.12.234.23.23
666.666.23.23
.213.123.23.32
23.45.22.32.
I.Am.not.an.ip
*/
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.Scanner;

class Regex {

    public static void main(String []args)
    {
        Scanner in = new Scanner(System.in);
        while(in.hasNext())
        {
            String IP = in.next();
            System.out.println(IP.matches(new myRegex().pattern));
        }

    }

class myRegex {
	public String pattern="([1][\\d][\\d]|[0][0][0]|([0][0]|)[\\d]|([0]|)[\\d][\\d]|[2][0-4][\\d]|[2][5][0-5])."
			+ "([1][\\d][\\d]|[0][0][0]|([0][0]|)[\\d]|([0]|)[\\d][\\d]|[2][0-4][\\d]|[2][5][0-5])."
			+ "([1][\\d][\\d]|[0][0][0]|([0][0]|)[\\d]|([0]|)[\\d][\\d]|[2][0-4][\\d]|[2][5][0-5])."
			+ "([1][\\d][\\d]|[0][0][0]|([0][0]|)[\\d]|([0]|)[\\d][\\d]|[2][0-4][\\d]|[2][5][0-5])";
	
}
}