Replacing String month with type Int - What to do!?!

Question

import java.util.Scanner;
public class Date
    private String month;
    private int day;
    private int year; //a four digit number.
    public Date( )
        month = "January";
        day = 1;
        year = 1000;
    public Date(int monthInt, int day, int year)
        setDate(monthInt, day, year);
    public Date(String monthString, int day, int year)
        setDate(monthString, day, year);
    public Date(int year)
        setDate(1, 1, year);
    public Date(Date aDate)
        if (aDate == null)//Not a real date.
             System.out.println("Fatal Error.");
             System.exit(0);
        month = aDate.month;
        day = aDate.day;
        year = aDate.year;
    public void setDate(int monthInt, int day, int year)
        if (dateOK(monthInt, day, year))
            this.month = monthString(monthInt);
            this.day = day;
            this.year = year;
        else
            System.out.println("Fatal Error");
            System.exit(0);
    public void setDate(String monthString, int day, int year)
        if (dateOK(monthString, day, year))
            this.month = monthString;
            this.day = day;
            this.year = year;
        else
            System.out.println("Fatal Error");
            System.exit(0);
    public void setDate(int year)
        setDate(1, 1, year);
    public void setYear(int year)
        if ( (year < 1000) || (year > 9999) )
            System.out.println("Fatal Error");
            System.exit(0);
        else
            this.year = year;
    public void setMonth(int monthNumber)
        if ((monthNumber <= 0) || (monthNumber > 12))
            System.out.println("Fatal Error");
            System.exit(0);
        else
            month = monthString(monthNumber);
    public void setDay(int day)
        if ((day <= 0) || (day > 31))
            System.out.println("Fatal Error");
            System.exit(0);
        else
            this.day = day;
    public int getMonth( )
        if (month.equals("January"))
            return 1;
        else if (month.equals("February"))
            return 2;
        else if (month.equalsIgnoreCase("March"))
            return 3;
        else if (month.equalsIgnoreCase("April"))
            return 4;
        else if (month.equalsIgnoreCase("May"))
            return 5;
        else if (month.equals("June"))
            return 6;
        else if (month.equalsIgnoreCase("July"))
            return 7;
        else if (month.equalsIgnoreCase("August"))
            return 8;
        else if (month.equalsIgnoreCase("September"))
            return 9;
        else if (month.equalsIgnoreCase("October"))
            return 10;
        else if (month.equals("November"))
            return 11;
        else if (month.equals("December"))
            return 12;
        else
            System.out.println("Fatal Error");
            System.exit(0);
            return 0; //Needed to keep the compiler happy
    public int getDay( )
        return day;
    public int getYear( )
        return year;
    public String toString( )
        return (month + " " + day + ", " + year);
    public boolean equals(Date otherDate)
        return ( (month.equals(otherDate.month))
                  && (day == otherDate.day) && (year == otherDate.year) );
    public boolean precedes(Date otherDate)
        return ( (year < otherDate.year) ||
           (year == otherDate.year && getMonth( ) < otherDate.getMonth( )) ||
           (year == otherDate.year && month.equals(otherDate.month)
                                         && day < otherDate.day) );
    public void readInput( )
        boolean tryAgain = true;
        Scanner keyboard = new Scanner(System.in);
        while (tryAgain)
            System.out.println("Enter month, day, and year.");
              System.out.println("Do not use a comma.");
            String monthInput = keyboard.next( );
            int dayInput = keyboard.nextInt( );
            int yearInput = keyboard.nextInt( );
            if (dateOK(monthInput, dayInput, yearInput) )
                setDate(monthInput, dayInput, yearInput);
                tryAgain = false;
            else
                System.out.println("Illegal date. Reenter input.");
    private boolean dateOK(int monthInt, int dayInt, int yearInt)
        return ( (monthInt >= 1) && (monthInt <= 12) &&
                 (dayInt >= 1) && (dayInt <= 31) &&
                 (yearInt >= 1000) && (yearInt <= 9999) );
    private boolean dateOK(String monthString, int dayInt, int yearInt)
        return ( monthOK(monthString) &&
                 (dayInt >= 1) && (dayInt <= 31) &&
                 (yearInt >= 1000) && (yearInt <= 9999) );
    private boolean monthOK(String month)
        return (month.equals("January") || month.equals("February") ||
                month.equals("March") || month.equals("April") ||
                month.equals("May") || month.equals("June") ||
                month.equals("July") || month.equals("August") ||
                month.equals("September") || month.equals("October") ||
                month.equals("November") || month.equals("December") );
    private String monthString(int monthNumber)
        switch (monthNumber)
        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";
        default:
            System.out.println("Fatal Error");
            System.exit(0);
            return "Error"; //to keep the compiler happy
}My question is that if I were to change the String month in the instance variables to type int, what changes do I make to the code to make this work WITHOUT changing the method headings and it also says that none of the type String paraenters should change to type int. I need to redefine the methods to make it work. I've been at this for hours and am just stuck so this is the reason for my early morning post.

Answer 1

import java.util.Scanner;
public class Date
    private int month;
    private int day;
    private int year; //a four digit number.
    public Date( )
        month = 1;
        day = 1;
        year = 1000;
    public Date(int monthInt, int day, int year)
        setDate(monthInt, day, year);
    public Date(String monthString, int day, int year)
        setDate(monthString, day, year);
    public Date(int year)
        setDate(1, 1, year);
    public Date(Date aDate)
        if (aDate == null)//Not a real date.
             System.out.println("Fatal Error.");
             System.exit(0);
        month = aDate.month;
        day = aDate.day;
        year = aDate.year;
    public void setDate(int monthInt, int day, int year)
        if (dateOK(monthInt, day, year))
            this.month = monthInt;
            this.day = day;
            this.year = year;
        else
            System.out.println("Fatal Error");
            System.exit(0);
    public void setDate(String monthString, int day, int year)
        if (dateOK(monthString, day, year))
            this.month = monthStringToInt(monthString);
            this.day = day;
            this.year = year;
        else
            System.out.println("Fatal Error");
            System.exit(0);
    public void setDate(int year)
        setDate(1, 1, year);
    public void setYear(int year)
        if ( (year < 1000) || (year > 9999) )
            System.out.println("Fatal Error");
            System.exit(0);
        else
            this.year = year;
    public void setMonth(int monthNumber)
        if ((monthNumber <= 0) || (monthNumber > 12))
            System.out.println("Fatal Error");
            System.exit(0);
        else
            month = monthNumber;
    public void setDay(int day)
        if ((day <= 0) || (day > 31))
            System.out.println("Fatal Error");
            System.exit(0);
        else
            this.day = day;
    public int getMonth( )
         return month;
    public int getDay( )
        return day;
    public int getYear( )
        return year;
    public String toString( )
        return (month + " " + day + ", " + year);
    public boolean equals(Date otherDate)
        return ( (month == otherDate.month)
                  && (day == otherDate.day) && (year == otherDate.year) );
    public boolean precedes(Date otherDate)
        return ( (year < otherDate.year) ||
           (year == otherDate.year && getMonth( ) < otherDate.getMonth( )) ||
           (year == otherDate.year && month == otherDate.month
                                         && day < otherDate.day) );
    public void readInput( )
        boolean tryAgain = true;
        Scanner keyboard = new Scanner(System.in);
        while (tryAgain)
            System.out.println("Enter month, day, and year.");
              System.out.println("Do not use a comma.");
            String monthInput = keyboard.next( );
            int dayInput = keyboard.nextInt( );
            int yearInput = keyboard.nextInt( );
            if (dateOK(monthInput, dayInput, yearInput) )
                setDate(monthInput, dayInput, yearInput);
                tryAgain = false;
            else
                System.out.println("Illegal date. Reenter input.");
    private boolean dateOK(int monthInt, int dayInt, int yearInt)
        return ( (monthInt >= 1) && (monthInt <= 12) &&
                 (dayInt >= 1) && (dayInt <= 31) &&
                 (yearInt >= 1000) && (yearInt <= 9999) );
    private boolean dateOK(String monthString, int dayInt, int yearInt)
        return ( monthOK(monthString) &&
                 (dayInt >= 1) && (dayInt <= 31) &&
                 (yearInt >= 1000) && (yearInt <= 9999) );
    private boolean monthOK(String month)
        return (month.equals("January") || month.equals("February") ||
                month.equals("March") || month.equals("April") ||
                month.equals("May") || month.equals("June") ||
                month.equals("July") || month.equals("August") ||
                month.equals("September") || month.equals("October") ||
                month.equals("November") || month.equals("December") );
    private String monthString(int monthNumber)
        switch (monthNumber)
        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";
        default:
            System.out.println("Fatal Error");
            System.exit(0);
            return "Error"; //to keep the compiler happy
    private int monthStringToInt(String monthString) {
         if (monthString.equals("January")) return 1;
         else if (monthString.equals("February")) return 2;
         else if (monthString.equals("March")) return 3;
         else if (monthString.equals("April")) return 4;
         else if (monthString.equals("May")) return 5;
         else if (monthString.equals("June")) return 6;
         else if (monthString.equals("July")) return 7;
         else if (monthString.equals("August")) return 8;
         else if (monthString.equals("September")) return 9;
         else if (monthString.equals("October")) return 10;
         else if (monthString.equals("November")) return 11;
         else if (monthString.equals("December")) return 12;
         else return -1;
}I've added one method: monthStringToInt to convert "January", "February" into an integer value. There are probably better ways to do this (Calendar), but this involes no other classes.