//8.7 Date.java
//Date class declaration

public class Date
{
    private int month; //1-12
    private int day; //1-31 based on month
    private int year; //any year

    private static final int[] daysPerMonth = //days in each month
        {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

    // constructor: call checkMonth to confirm proper value for month;
    // call checkDay to confirm proper value for day
    public Date (int theMonth, int theDay, int theYear)
    {
        month = checkMonth( theMonth ); // validate month
        year = theYear; // could validate year
        day = checkDay( theDay ); // validate day

        System.out.printf("Date object constructor for date %s\n", this );
    } //end Date constructor

    //utility method to confirm poper month value
    private int checkMonth (int testMonth)
    {
        if (testMonth > 0 && testMonth <= 12) // validate month
            return testMonth;
        else //month is invalid
            throw new IllegalArgumentException ("month must be 1-12");
    } //end method checkMonth

    // utility method to confirm proper day value based on month and year
    private int checkDay( int testDay )
    {
        // check if day in range for month
        if ( testDay > 0 && testDay <= daysPerMonth[ month ] )
            return testDay;

        // check for leap year
        if ( month == 2 && testDay == 29 && ( year % 400 == 0 ||
            ( year % 4 == 0 && year % 100 != 0 ) ) )
           return testDay;

        throw new IllegalArgumentException(
            "day out-of-range for the specified month and year" );
    } // end method checkDay

    // return a String of the form month/day/year
    public String toString()
    {
        return String.format( "%d/%d/%d", month, day, year );
    } // end method toString
} // end class Date