Counting the right data formats-CodePudding

im stuck at a problem where i need to make a class which counts all the right data formats given to a string.

Requirement: Write a ValidatorDate class that contains the following public countValidData enumeration.

The method will receive as a parameter a string of Strings (String[]) and will return an int representing the number of Strings in the string that respect the format dd/mm/yyyy.

Signature:

public static int countValidData(String[] words)

Example:

//Your class here
    public class prog {
      public static void main(String[] args) {
        System.out.println(ValidatorDate.countValidData(new String[]{"Today", "is", "01/04/2019", "01/13/2019",
          "29/02/200s"}));
        // 2
      }
    }

and this is what i've done so far

import java.util.Arrays;
import java.util.regex.Pattern;

class ValidatorDate {

    static int countValidData(String[] arrayDate) {

        Pattern regexPattern = Pattern.compile("^\\d{2}/\\d{2}/\\d{4}$");

        int counter = 0;

        for (String currentWord : arrayDate) {


            if (regexPattern.matcher(currentWord).matches()) {

                counter  ;

            }

        }

        return counter;
    }
}

This code needs a fix, if i introduce for example, the following date: "99/99/9999" it sees it as a valid date, i dont have this "only 12 months" and "30 or 31 days, or 28 in february" implementation, can someone help me with it? Thanks in advance!

CodePudding user response：

Use DateTimeFormatter

static int countValidData(String[] arrayDate) {
    int counter = 0;

    for (String currentWord : arrayDate) {
       try {
           DateTimeFormatter.ofPattern("dd/MM/yyy").parse(currentWord);
           counter  ;
       }catch (DateTimeParseException e){
            //log to  see what is wrong
       }

    }

    return counter;
}

CodePudding user response：

First import as needed

import java.time.format.DateTimeFormatter;
import java.time.LocalDate;

Now, you can utilize DateTimeFormatter and LocalDate

static int countValidData(String[] arrayDate) {
    
        //Initialize DateTimeFormatter
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");

        int counter = 0;

        for (String currentWord : arrayDate) {

            try {
                
                //Try to convert String to LocalDate
                LocalDate localDate = LocalDate.parse(date, formatter);
                
                //Increment counter by 1
                counter  = 1;
                
            } catch (Exception e){
                //If an exception was thrown, the date is invalid
            }

        }

        return counter;
}