Period and Duration

Part of the Logic & Flow section of Coddy's Java journey. Lesson 57 of 59.

Period represents a date-based amount of time (years, months, days), while Duration represents a time-based amount (hours, minutes, seconds).

Create a Period:

Period period = Period.of(1, 2, 15);
// 1 year, 2 months, 15 days

Create a Duration:

Duration duration = Duration.ofHours(2);
// 2 hours
Duration minutes = Duration.ofMinutes(90);
// 90 minutes

After executing the above code, period contains:

P1Y2M15D  // ISO-8601 format

Measure the gap between two dates with Period.between(). It takes two LocalDate values and splits the gap into years, months and days:

LocalDate start = LocalDate.of(2024, 1, 15);
LocalDate end = LocalDate.of(2025, 3, 20);
Period p = Period.between(start, end);
p.getYears();   // 1
p.getMonths();  // 2
p.getDays();    // 5

getDays() returns only the days left over after the whole years and months, not the total number of days between the two dates. A LocalDateTime gives you its date with toLocalDate().

Measure the gap between two times with Duration.between(), which takes two LocalDateTime (or LocalTime) values:

LocalDateTime from = LocalDateTime.of(2024, 3, 15, 10, 30);
LocalDateTime to = LocalDateTime.of(2024, 3, 15, 14, 45);
Duration d = Duration.between(from, to);
d.toHours();        // 4
d.toMinutes();      // 255
d.toMinutesPart();  // 15

toMinutes() counts the whole gap in minutes, hours included. toMinutesPart() gives the minutes left over after the whole hours, so this gap is 4 hours and 15 minutes.

Challenge

Easy

Create a method named calculateDifference that takes four arguments:

A String (start) in format "yyyy-MM-dd HH:mm"
A String (end) in format "yyyy-MM-dd HH:mm"
A String (unit) either "period" or "duration"
A String (format) either "full" or "simple"

The method should:

Calculate the difference between start and end dates
Return the difference in the specified format

Return messages should be:

If invalid dates: return "Invalid date format"
If invalid unit: return "Invalid unit"
If invalid format: return "Invalid format"
For period with "full" format: "Years: X, Months: Y, Days: Z"
For period with "simple" format: "XyYmZd"
For duration with "full" format: "Hours: X, Minutes: Y", where Y is the minutes left over after the whole hours
For duration with "simple" format: "XhYm"

Try it yourself

import java.util.Scanner;
import java.time.*;
import java.time.format.*;

public class Main {
    public static String calculateDifference(String start, String end, String unit, String format) {
        // Write your code here
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String start = scanner.nextLine();
        String end = scanner.nextLine();
        String unit = scanner.nextLine();
        String format = scanner.nextLine();
        
        System.out.println(calculateDifference(start, end, unit, format));
    }
}