D&A Aufgabensatz 4 - Date

Date.java

/**
 * Primitive Datumsklasse in der Monate immer 30 Tage lang sind,
 * es keine Schaltjahre gibt und die Zeit aussen vor gelassen
 * wird. Diese Datumsklasse funktioniert nur mit Daten die jünger
 * als der 1.1.2000 sind.
 * 
 * @author Andy Villiger
 */
public class Date {
    
    private int timestamp;
    
    public Date(int day, int month, int year) {
        if (year < 2000) { year += 2000; }
        if (month < 1) { month = 1; }
        if (month > 12) { month = 12; }
        if (day < 1) { day = 1; }
        if (day > 30) { day = 30; }
        
        timestamp = (day - 1) + ((month - 1) * 30) + (year * 360);
    }
    
    public Date(int timestamp) {
        this.timestamp = timestamp;
    }
    
    public int getTimestamp() {
        return timestamp;
    }
    
    public int getDay() {
        return (timestamp % 30) + 1;
    }
    
    public int getMonth() {
        return (timestamp / 30 % 12) + 1;
    }
    
    public int getYear() {
        return (timestamp / 360);
    }
    
    public Date next() {
        return plus(1);
    }
    
    public Date previous() {
        return plus(-1);
    }
    
    public Date plus(int days) {
        return new Date(timestamp + days);
    }
    
    public Date between(Date other) {
        return new Date((timestamp + other.getTimestamp()) / 2);
    }
    
    public boolean isBefore(Date other) {
        return (timestamp < other.getTimestamp());
    }
    
    public boolean isAfter(Date other) {
        return (timestamp > other.getTimestamp());
    }
    
    public boolean equal(Date other) {
        return (timestamp == other.getTimestamp());
    }
    
    @Override
    public String toString() {
        return getDay() + "." + getMonth() + "." + getYear();
    }
    
    public static void main(String[] args) {
        Date date = new Date(9, 11, 12);
        
        System.out.println(date);
        System.out.println(date.plus(60));
        System.out.println(date.plus(-35));
        System.out.println(date.isBefore(date.plus(1)));
        System.out.println(date.isAfter(date.plus(1)));
        System.out.println(date.equal(date.plus(1).plus(-1)));
    }
}