CalendarApp.java

package net.calendar.app;

import java.io.PrintStream;
import java.util.Calendar;
import java.util.Scanner;

public final class Program
{
  public Program() {}
  
  public static void main(String[] args)
  {
    Program p = new Program();
    int year = 0;int start = 0;
    Scanner scin = new Scanner(System.in);
    p.print("Please enter a Year: ");
    
    year = scin.nextInt();
    Calendar cal = Calendar.getInstance();
    cal.clear();
    cal.set(year, 0, 0);
    start = cal.get(7);
    if (start > 6)
      start = 0;
    for (int month = 1; month <= 12; month++) {
      p.printOneMonth(month, year, start);
      start = (start + p.daysOfMonth(month, year, true)) % 7;
      
      p.print("Enter random text and press enter...\r\n");
      scin.next();
      
      p.println();
    }
  }
  
  public void println() {
    System.out.println();
  }
  
  public void println(Object o) {
    System.out.println(o);
  }
  
  public void print(Object o) {
    System.out.print(o);
  }
  
  public boolean isLeapYear(int year) {
    return ((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0);
  }
  
  public String printMonthName(int month) {
    switch (month) {
    case 1: 
      return "January";
    case 2: 
      return "February";
    case 3: 
      return "March";
    case 4: 
      return "April";
    case 5: 
      return "May";
    case 6: 
      return "June";
    case 7: 
      return "July";
    case 8: 
      return "August";
    case 9: 
      return "September";
    case 10: 
      return "October";
    case 11: 
      return "November";
    case 12: 
      return "December";
    }
    return "Not a valid month";
  }
  
  public int printWeekTitle(int month, int day, int year) {
    Calendar cal = Calendar.getInstance();
    cal.clear();
    cal.set(year, month, day);
    return cal.get(3);
  }
  
  public void printOneMonth(int month, int year, int start) {
    int nextDay = start;
    int totalDays = daysOfMonth(month, year, false);
    




    System.out.printf("%10s%10s%10s%10s%10s%10s%10s", new Object[] { "Sun", "Mon", "Tue", 
      "Wed", "Thu", "Fri", "Sat" });
    println();
    for (int i = 1; i <= start; i++) {
      System.out.printf("%10s", new Object[] { "" });
    }
    for (int dates = 1; dates <= totalDays; dates++) {
      System.out.printf("%10d", new Object[] { Integer.valueOf(dates) });
      nextDay = (nextDay + 1) % 7;
      if (nextDay == 0)
        println();
    }
    println();
  }
  
  public int daysOfMonth(int month, int year, boolean suppressMessage)
  {
    if (!suppressMessage) {
      String format = String.format(
        "Calculating the days of the Month of %s in %s", new Object[] {
        printMonthName(month), Integer.valueOf(year) });
      println(format);
    }
    switch (month)
    {
    case 1: 
    case 3: 
    case 5: 
    case 7: 
    case 8: 
    case 10: 
    case 12: 
      if (!suppressMessage)
        println("The Month of " + printMonthName(month) + " has " + 31 + 
          " days.");
      return 31;
    

    case 4: 
    case 6: 
    case 9: 
    case 11: 
      if (!suppressMessage)
        println("The Month of " + printMonthName(month) + " has " + 31 + 
          " days.");
      return 30;
    

    case 2: 
      if (isLeapYear(year)) {
        if (!suppressMessage)
          println("The Month of " + printMonthName(month) + " has " + 
            31 + " days.");
        return 29;
      }
      if (!suppressMessage)
        println("The Month of " + printMonthName(month) + " has " + 
          31 + " days.");
      return 28;
    }
    
    return 0;
  }
}