/*
Date 			: 		10 October 2013
Author			:		Shivam Tiwari [shivamtiwari1011@gmail.com]
Organization	:		http://mycodedock.blogspot.in/
Description		:		http://mycodedock.blogspot.in/2013/10/the-task-is-to-create-tool-in-java-that.html
*/
 
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class Main{
	public static void main(String[] args){
 
		//declaring required variables
		String inputString, findPattern;
 
		//creating a new Scanner object
		Scanner scannerObj = new Scanner(System.in);
 
		/*
		(0?[1-9]|[12][0-9]|3[01])
		day can be 01, 02....09
		OR day can be 1,2....9
		OR day can be 10,11....19
		OR day can be 20,21....29
		OR day can be 30, 31
 
		followed by /
 
		(0?[1-9]|1[012])
		month can be 01,02...09
		OR month can be 1,2...9
		OR month can be 10, 11, 12
 
		followed by /
 
		((19|20)\\d\\d)
		year can be 19 followed by digit followed by a digit
		OR year can be 20 followed by a digit followed by a digit
		*/
		findPattern = "(0?[1-9]|[12][0-9]|3[01])/(0?[1-9]|1[012])/((19|20)\\d\\d)";
 
		System.out.println("Enter date string : ");
 
		//get inputString
		inputString = scannerObj.nextLine();
 
		//create a pattern object
		Pattern patternObj = Pattern.compile(findPattern);
 
		//create a matcher object
		Matcher matcherObj = patternObj.matcher(inputString);
 
		if(matcherObj.find()){
			System.out.println("This is a valid date string : " + inputString);
		}
		else{
			System.out.println("This is NOT a valid date string : " + inputString);
		}
	}
}