Calendar operations
/*
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();
}
}
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