// Implements a a second in time that occurs on January 1, 1753 or later.
// The invariant is maintained that the moment is a legitimate hour, minute,
// second on a legitimate date, expressed in AM/PM format, or else an 
// illegitimate moment of where the month, day, year, minute, second 
// are all 0, PM is false, and hour is 12
public interface MomentInterface extends DateInterface, Comparable
{
    // getters
    int getHour();
    int getHourMilitary();    // hour in military time (0-23)
    int getMinute();  // 0-59
    int getSecond();  // 0-59
    boolean getPM();  // false if A.M., true if P.M.
   
    // preconditions:  none
    // postcondition:  true has been returned if the moment is a legitimate
    //   one, and false otherwise
    boolean isLegal();

    // precondition:  none
    // postcondition:  an exception has been thrown if either of the moments
    //   is an illegitimate one; otherwise, it returns the number of
    //   seconds from 'this' to m2.  This value is negative if
    //   m2 is before 'this'.
    int secondsUntil(MomentInterface m2);
    
    // precondition:  none
    // postcondition:  an exception has been thrown if either of the moments
    //   is an illegitimate one; otherwise, it returns the number of
    //   minutes from the moment to m2, *rounded to the nearest minute*
    //   (half a minute rounds up if the result is positive, and down if 
    //   the result is negative)
    int minutesUntil(MomentInterface m2);
    
    // precondition:  none
    // postcondition:  an exception has been thrown if either of the moments
    //   is an illegitimate one; otherwise, it returns the number of
    //   hours from the moment to m2, *rounded to the nearest hour*
    //   (half an hour rounds up if the result is positive, and down if 
    //   the result is negative)
    int hoursUntil(MomentInterface m2);

    // precondition:  o2 is of a type that implements MomentInterface
    // postcondition:  returns -1 if 'this' is before o2, 0 if they are the 
    // same, 1 if 'this' is after o2.  Throws an exception, prints the
    // stack trace and halts if one of the two is an illegal moment.  The
    // error should indicate whether 'this' or the parameter caused the
    // exception.
    int compareTo(Object o2);
    
    // Precondition:  none
    // Outputs string in the format m/d/y hour:min:sec AM/PM
    // Example:  2/26/2012 10:36 AM;  0/0/0 12:0:0 AM
    String toString();

    // In addition, an implementation should have a default constructor
    // that returns 0/0/0 12:0:0 AM.  It should have a constructor
    // that takes (month, day, year, hour (American format), minute, second,
    // boolean PM).  It should have a copy constructor that takes
    // a MomentInterface object as a parameter and creates a copy
    // of the moment as an object in the class that implements it.
}