Printing all days of the week

[Daan Heuvelbeuk]

In part of my program I try to get the dates of this week assigned to a JComboBox. While developing I check my results. And the result is not to my liking. Might you have a suggestion for me?

import java.text.SimpleDateFormat;
import java.time.*;
import java.time.format.DateTimeFormatter;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;

public class DateChooser {
	private static void calculateDays() {
		TimeZone timeZone = TimeZone.getTimeZone("Europe/Amsterdam");
		SimpleDateFormat dayFormat = new SimpleDateFormat("dd-MM-yyyy"); 
		
		// Find this weeks monday date
		LocalDate today = LocalDate.now();
		LocalDate monday = today.minusDays(today.getDayOfWeek().getValue() - 1);
		
		Instant instant = monday.atStartOfDay().atZone(ZoneId.systemDefault()).toInstant();
		Date date = Date.from(instant);
		
		Calendar calendar = new GregorianCalendar(timeZone);
		calendar.setTime(date);

		String dayString = dayFormat.format(date);
		for (int i = 0; i < 6; i++) {
			calendar.add(Calendar.DATE, i);
			date = calendar.getTime();
			System.out.println ("getDates - date=" + date); 
			dayString = dayFormat.format(date);
			System.out.println("getDates - dayString=" + dayString);
		}	
	}

    public static void main(String[] args) {
    	calculateDays();
    }
}

In this code I decide on what date this weeks Monday is. From that date I print out the dates of this weeks days. For this week beginning Monday September 28th I would get a list of:

28-09-2015
29-09-2015
30-09-2015
01-10-2015
02-10-2015
03-10-2015
04-10-2015

But in the code above I get the following list:

getDates - date=Mon Sep 28 00:00:00 CEST 2015
getDates - dayString=28-09-2015
getDates - date=Tue Sep 29 00:00:00 CEST 2015
getDates - dayString=29-09-2015
getDates - date=Thu Oct 01 00:00:00 CEST 2015
getDates - dayString=01-10-2015
getDates - date=Sun Oct 04 00:00:00 CEST 2015
getDates - dayString=04-10-2015
getDates - date=Thu Oct 08 00:00:00 CEST 2015
getDates - dayString=08-10-2015
getDates - date=Tue Oct 13 00:00:00 CEST 2015
getDates - dayString=13-10-2015
getDates - date=Mon Oct 19 00:00:00 CEST 2015
getDates - dayString=19-10-2015

I did some searching on the internet. I used the suggestion in How can I increment a date by one day in Java?

[Knute Snortum]

I think the problem is in this line.

calendar.add(Calendar.DATE, i);

[Campbell Ritchie]

Don't mix LocalDate and Calendar. You are right to use LocalDate, so stop using Calendar. Have you been through the Java™ Tutorials about dates? I am pretty sure you can get a date object for “next Monday” or “last Friday”.

They say local date is immutable and show an example with 14th May. I always thought they used 23rd May, which is Duke's Birthday

Try the section called Date Classes for an example with “next Wednesday”.

[Daan Heuvelbeuk]

Campbell Ritchie wrote:Don't mix LocalDate and Calendar. You are right to use LocalDate, so stop using Calendar.

Righto. Thanks.