CalendarTest.java Source code

Introduction

Here is the source code for CalendarTest.java

Source

/*
 This program is a part of the companion code for Core Java 8th ed.
 (http://horstmann.com/corejava)
    
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
    
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
    
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.text.DateFormatSymbols;
import java.util.Calendar;
import java.util.GregorianCalendar;

/**
 * @version 1.4 2007-04-07
 * @author Cay Horstmann
 */

public class CalendarTest {
    public static void main(String[] args) {
        // construct d as current date
        GregorianCalendar d = new GregorianCalendar();

        int today = d.get(Calendar.DAY_OF_MONTH);
        int month = d.get(Calendar.MONTH);

        // set d to start date of the month
        d.set(Calendar.DAY_OF_MONTH, 1);

        int weekday = d.get(Calendar.DAY_OF_WEEK);

        // get first day of week (Sunday in the U.S.)
        int firstDayOfWeek = d.getFirstDayOfWeek();

        // determine the required indentation for the first line
        int indent = 0;
        while (weekday != firstDayOfWeek) {
            indent++;
            d.add(Calendar.DAY_OF_MONTH, -1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
        }

        // print weekday names
        String[] weekdayNames = new DateFormatSymbols().getShortWeekdays();
        do {
            System.out.printf("%4s", weekdayNames[weekday]);
            d.add(Calendar.DAY_OF_MONTH, 1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
        } while (weekday != firstDayOfWeek);
        System.out.println();

        for (int i = 1; i <= indent; i++)
            System.out.print("    ");

        d.set(Calendar.DAY_OF_MONTH, 1);
        do {
            // print day
            int day = d.get(Calendar.DAY_OF_MONTH);
            System.out.printf("%3d", day);

            // mark current day with *
            if (day == today)
                System.out.print("*");
            else
                System.out.print(" ");

            // advance d to the next day
            d.add(Calendar.DAY_OF_MONTH, 1);
            weekday = d.get(Calendar.DAY_OF_WEEK);

            // start a new line at the start of the week
            if (weekday == firstDayOfWeek)
                System.out.println();
        } while (d.get(Calendar.MONTH) == month);
        // the loop exits when d is day 1 of the next month

        // print final end of line if necessary
        if (weekday != firstDayOfWeek)
            System.out.println();
    }
}