DisplayCalendar

package displaycalendar;

/**
 *
 * @author Patrick
 */
import java.util.Calendar;
import java.util.Scanner;
import java.util.GregorianCalendar;

public class DisplayCalendar {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        Calendar calendar = new GregorianCalendar();


        input.nextLine(); //make sure previous line is clear
        System.out.println("Please enter the date as numbers with spaces in between"
                + "(example: day month year), "
                + "\nthe current date will be displayed if insufficient data is given: ");

        //read the line and scan for each integer in it
        String lineBuffer = input.nextLine();
        Scanner dateScanner = new Scanner(lineBuffer);

        int day = dateScanner.nextInt();
        int month = dateScanner.nextInt();
        int year = dateScanner.nextInt();

        if (month == 0){
            month = (calendar.get(Calendar.MONTH) + 1);
        }
        if (year == 0){
            year = calendar.get(Calendar.YEAR);
        }

        //print statement here
        printMonthTitle(year, month);
        printMonthBody(year, month);

    }

    //print month title
    public static void printMonthTitle(int year, int month){
        System.out.println("       " + getMonthName(month) +
                " " + year);
        System.out.println("------------------------------");
        System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
    }

    //getMonthName
    public static String getMonthName(int month){
        String monthName = "";

        switch(month){
            case 1: monthName = "January";
            case 2: monthName = "February";
            case 3: monthName = "March";
            case 4: monthName = "May";
            case 5: monthName = "April";
            case 6: monthName = "May";
            case 7: monthName = "June";
            case 8: monthName = "July";
            case 9: monthName = "August";
            case 10: monthName = "Septemner";
            case 11: monthName = "November";
            case 12: monthName = "December";
        }
        return monthName;
    }

    //printMonthBody
    public static void printMonthBody(int year, int month){

        int startDay = getStartDay(year, month);

        int numberOfDaysInMonth = getNumberOfDaysInMonth(year, month);

        int i = 0;
        for(i = 0; i <startDay; i++){
            System.out.println("    ");

            if((i + startDay) % 7 == 0)
                System.out.println();
        }

        System.out.println();
    }

    //get start day of month/1/year
    public static int getStartDay(int year, int month){
        final int START_DAY_FOR_JAN_1_1800 = 3;

        int totalNumberOfDays = getTotalNumberOfDays(year, month);

        return totalNumberOfDays;
    }

    //get the total number of days
    public static int getTotalNumberOfDays(int year, int month){
        int total = 0;

        for(int i = 1800; i < year; i++){
            if(isLeapYear(i))
                total = total + 366;
            else
                total = total + 365;
        }

        for(int i = 1; i < month; i++)
            total = total + getNumberOfDaysInMonth(year, i);

        return total;
    }

    //get # days in month
    public static int getNumberOfDaysInMonth(int year, int month){
        if(month == 1 || month == 3 || month == 5 || month == 7 ||
                month == 8 || month == 10 || month == 12)
            return 31;

        if(month == 4 || month == 6 || month == 9 || month == 11)
            return 30;

        if(month == 2) return isLeapYear(year) ? 29 : 28;
        return 0;
    }

    public static boolean isLeapYear(int year){
        return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
    }

}