Java tutorial
public class Time implements Comparable { private int hour, minute; public Time(int hh, int mm) { this.hour = hh; this.minute = mm; } public int compareTo(Object o) { Time t = (Time) o; return hour != t.hour ? hour - t.hour : minute - t.minute; } public boolean equals(Object o) { Time t = (Time) o; return hour == t.hour && minute == t.minute; } public int hashCode() { return 60 * hour + minute; } }