uproszczone md2

package com.company;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.stream.Collectors;

class Mileage {//odczyty przebiegu
    int kilometers;
    String vin; // asocjacja z atrybutu
    Date date;

    public Mileage(int kilometers, String vin, Date date) {
        this.kilometers = kilometers;
        this.vin = vin;
        this.date = date;
    }

    static List<Mileage> mileageList = new ArrayList<>();

    static List<Mileage> getAllValuesByVin(String byVin) {

        return mileageList.stream().filter(record -> record.vin.equals(byVin)).collect(Collectors.toList());
    }

    static void addMileageRecord(Mileage mileageToAdd) {
        mileageList.add(mileageToAdd);
    }

}

class Car implements Comparable<Car> {
    String brand;
    String model;
    String vin;

    static Map<Car, Client> carOwners = new TreeMap<>(); // asocjacja kwalifikowana

    public static void addOwnerToCar(Client owner, Car car) {
        if (carOwners.containsKey(car)) {
            throw new IllegalArgumentException("Car already has his owner! you have to remove it first");
        }
        carOwners.put(car, owner);
    }

    public static Client getCarOwner(Car car) {
        if (carOwners.containsKey(car)) {
            return carOwners.get(car);
        }
        throw new IllegalArgumentException("this car has no owner");
    }

    @Override
    public int compareTo(Car o) {
        return vin.compareTo(o.vin);
    }
}

class Purchase { // zakup czyli przyklad asocjacji z atrybutem
    Client client;
    Car car;
    Date purchaseDate;
    int price;

    public Purchase(Client client, Car car, Date purchaseDate, int price) {
        this.client = client;
        this.car = car;
        this.purchaseDate = purchaseDate;
        this.price = price;
    }
}

class Discount {

    private Discount(int percentage, String name) {
        this.percentage = percentage;
        this.name = name;
    }

    private int percentage;
    private String name;

    static Discount NewClientDiscount = new Discount(10, "Discount for new clients");
    static Discount NextCarDiscount = new Discount(12, "Discount for next car");

}

public class Client {

    public static void main(String[] args) {
        ArrayList<Discount> discountList = new ArrayList<>();
        discountList.add(Discount.NewClientDiscount);
        discountList.add(Discount.NextCarDiscount);
        Client client = new Client("Jan", 1, discountList, "jan@wp.pl", new Date(), "90121912312");
        Client client2 = new Client("Maciej", "Tomasz", 1, discountList, "maciej@wp.pl", new Date(), "14253112670");
        Client client3 = new Client("Bogdan", 3, discountList, "bogdan@wp.pl", new Date(), "80121912312");
    }

    private String name;
    private String secondName;                          //atrybut opcjonalny
    private long id;                                    //atrybut prosty
    private final ArrayList<Discount> discountList = new ArrayList<>();      // asocjacja binarna
    private String email;                               //atrybut wymagany
    private Date creationDate;                          // atrybut zlozony
    private String pesel;
    private Client customerReferral;// asocjacja rekurencyjna, pole oznacza ze klient zostal polecony przez inego klienta

    public Client getCustomerReferral() {
        return customerReferral;
    }

    public void setCustomerReferral(Client customerReferral) {
        this.customerReferral = customerReferral;
    }

    private Client(String name, long id, ArrayList discountList, String email, Date creationDate, String pesel) {
        this.name = name;
        this.id = id;
        this.discountList.addAll(discountList);
        this.email = email;
        this.creationDate = creationDate;
        this.pesel = pesel;
    }

    private Client(String name, String secondName, long id, ArrayList discountList, String email, Date creationDate, String pesel) {
        this(name, id, discountList, email, creationDate, pesel);
        this.secondName = secondName;
    }

}