import java.io.PrintWriter; import java.text.DateFormatSymbols; import java.util.Date; import java.util.Dictionary; import java.util.Hashtable; import java.util.Locale; public class Calendar { // following is identical to JSP private static final Dictionary dates = new Hashtable(); static { // certainly not an exhaustive list, // but at least one per month dates.put("1/27", "Wolfgang Amadeus Mozart, 1756"); dates.put("2/3", "Felix Mendelssohn, 1809"); dates.put("2/23", "Georg Friedrich Handel, 1685"); dates.put("3/21", "Johann Sebastian Bach, 1685"); dates.put("3/25", "Bela Bartok, 1881"); dates.put("3/31", "Franz Joseph Haydn, 1732"); dates.put("4/27", "Sergei Prokofiev, 1891"); dates.put("5/5", "Johannes Brahms, 1833"); dates.put("6/2", "Sir Edward Elgar, 1857"); dates.put("6/15", "Edward Grieg, 1843"); dates.put("7/3", "Leos Janacek, 1854"); dates.put("7/7", "Gustav Mahler, 1860"); dates.put("8/22", "Claude Debussy, 1862"); dates.put("9/4", "Anton Bruckner, 1824"); dates.put("9/8", "Anton Dvorak, 1841"); dates.put("9/26", "George Gershwin, 1898"); dates.put("10/20", "Charles Ives, 1874"); dates.put("10/22", "Franz List, 1811"); dates.put("11/18", "Carl Weber, 1786"); dates.put("12/10", "Cesar Franck, 1822"); dates.put("12/15", "Ludwig van Beethoven, 1770"); dates.put("12/30", "Dmitri Kabalevsky, 1904"); } // above is identical to JSP public static void main(String[] args) { PrintWriter writer = new PrintWriter(System.out, true); // get requested month/year int calendarMonth; int calendarYear; int month = args.length == 0 ? Integer.MAX_VALUE : Integer.parseInt(args[0]); int year = args.length == 0 ? Integer.MAX_VALUE : Integer.parseInt(args[1]); output(writer, month, year); writer.flush(); writer.close(); } public static void output(PrintWriter out, int calendarMonth, int calendarYear) { // following is almost identical to JSP // differences: // - input argument handling // - links are removed Locale locale = Locale.getDefault(); String event; java.util.Calendar calendar = java.util.Calendar.getInstance(locale); int firstDayOfWeek = calendar.getFirstDayOfWeek(); DateFormatSymbols dateFormatSymbols = new DateFormatSymbols(locale); // weekday names is one-based; [0] is empty String[] dayNames; { String[] originalDayNames = dateFormatSymbols.getShortWeekdays(); dayNames = new String[originalDayNames.length-1]; System.arraycopy( originalDayNames, firstDayOfWeek, dayNames, 0, dayNames.length-(firstDayOfWeek-1)); if ( firstDayOfWeek != 1 ) { System.arraycopy( originalDayNames, 1, dayNames, dayNames.length-(firstDayOfWeek-1), firstDayOfWeek-1); } } String[] monthNames = dateFormatSymbols.getMonths(); // get info about today int thisDay = calendar.get(java.util.Calendar.DAY_OF_MONTH); int thisMonth = calendar.get(java.util.Calendar.MONTH); int thisYear = calendar.get(java.util.Calendar.YEAR); if ( calendarMonth == Integer.MAX_VALUE ) { calendarMonth = thisMonth; } if ( calendarYear == Integer.MAX_VALUE ) { calendarYear = thisYear; } String monthName = monthNames[calendarMonth]; calendar.set(java.util.Calendar.DAY_OF_MONTH, 1); calendar.set(java.util.Calendar.MONTH, calendarMonth); calendar.set(java.util.Calendar.YEAR, calendarYear); // what weekday is the first day of the month? int firstWeekdayOfMonth = calendar.get(java.util.Calendar.DAY_OF_WEEK); // calendarDay contains the day of the month. It is initialized to // a negative value and incremented for each cell in the calendar // so that its value is 1 on the cell for the first day of the month. int calendarDay = 1 + firstDayOfWeek - firstWeekdayOfMonth; // what's the last day of the month? calendar.add(java.util.Calendar.MONTH, 1); calendar.add(java.util.Calendar.DAY_OF_MONTH, -1); int lastDayOfMonth = calendar.get(java.util.Calendar.DAY_OF_MONTH); int lastWeekOfMonth = calendar.get(java.util.Calendar.WEEK_OF_MONTH); // above is identical to JSP } } monthName + " " + calendarYear monthName + " " + calendarYear dayNames dayName int weekOfMonth = 0; weekOfMonth < lastWeekOfMonth; ++weekOfMonth int dayOfWeek = 0; dayOfWeek < dayNames.length; ++dayOfWeek, ++calendarDay calendarDay == thisDay && calendarMonth == thisMonth && calendarYear == thisYear today 1 <= calendarDay && calendarDay <= lastDayOfMonth ? "this-month" : "other-month" 1 <= calendarDay && calendarDay <= lastDayOfMonth ? String.valueOf(calendarDay) : " " null != (event = (String) dates.get(String.valueOf(calendarMonth+1) + "/" + String.valueOf(calendarDay))) event