// Fig. 8.9: 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

  // 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.println( "Date object constructor for date " +
                        toDateString() );

  } // end Date constructor

  // utility method to confirm proper month value
  private int checkMonth( int testMonth )
  {
    if ( testMonth > 0 && testMonth <= 12 )  // validate month
      return testMonth;
    else { // month is invalid
      System.out.println( "Invalid month (" + testMonth +
                          ") set to 1." );
      return 1;  // maintain object in consistent state
    }

  } // end method checkMonth

  // utility method to confirm proper day value based on month and year
  private int checkDay( int testDay )
  {
    int daysPerMonth[] =
    { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

    // 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;

    System.out.println( "Invalid day (" + testDay + ") set to 1." );

    return 1;  // maintain object in consistent state

  } // end method checkDay

  // return a String of the form month/day/year
  public String toDateString()
  {
    return month + "/" + day + "/" + year;
  }

} // end class Date