/******************************* FILE HEADER **********************************
    Main:        Oops4.java
    File:        Date.java
    
    Author:      James D. Skrentny, skrentny@cs.wisc.edu
                 copyright 2000 all rights reserved
    Course:      CS 302: Lectures 1 & 2
    
    Compiler:    CodeWarrior IDE 4.0 (JDK 1.2)
    Platform:    Windows NT 4.0
 **************************** 80 columns wide *********************************/

/**
 * A more complete Date class that insures invalid dates cannot be
 * created.  If a bad date is given, an InvalidDateException is thrown.
 *
 * BUGS: none known
 **/
 class Date {
 
    private int day, year;
    private String month;
    public final String[ ] months = {"Jan", "Feb", "Mar", "Apr", "May",
                 "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
    public final int[ ] monthDays = {31, 28, 31, 30, 31, 30, 31, 31,
                                        30, 31, 30, 31};
    
    public Date (int day, String month, int year) {
        this.day = day;
        this.month = month;
        this.year = year;
        if (!yearOK())
            throw new InvalidDateException(3);
        if (!monthOK())
            throw new InvalidDateException(2);
        // must check day last since depends on month and year
        if (!dayOK())
            throw new InvalidDateException(1);
    }
    
    public void setDay  (int day)   {
        this.day  = day;
        if (!dayOK())
            throw new InvalidDateException(1);
    }
    
    public void setMonth(String month) {
        this.month = month;
        if (!monthOK())
            throw new InvalidDateException(2);
        //day may not be valid for new month
        if (!dayOK())
            throw new InvalidDateException(1);
    }
    
    public void setYear (int year)  {
        this.year  = year;
        if (!yearOK())
            throw new InvalidDateException(3);
        //day may not be valid for new year (i.e. leap years)
        if (!dayOK())
            throw new InvalidDateException(1);
    }
    
    public int getDay () {
        return this.day;
    }
    
    public String getMonth () {
        return this.month;
    }
    
    public int getYear () {
        return this.year;
    }
    
    public boolean isLeapYear (int year) {
        if (year%4 == 0 && year%100 != 0
            || year%400 == 0 && year%3600 != 0) return true;
        return false; 
    }
        
    public String toString () {
        return this.month + " " + this.day + ", " + this.year;
    }

    private int findMonth (String month) {
        for (int i = 0; i < months.length; i++)
            if (month .equals(months[i])) return i;
        return -1;
    }
    
    private boolean dayOK () {
        int i = findMonth(month);
        if (i == 1 && isLeapYear(this.year)
            && this.day >= 1 && this.day <= 29) return true;
        if (i != -1
            && this.day >= 1 && this.day <= monthDays[i]) return true;
        return false; 
    }
    
    private boolean monthOK () {
        if (findMonth(this.month) != -1) return true;
        return false; 
    }
    
    private boolean yearOK () {
        if (this.year > 0) return true;
        return false; 
    }
}