Order.java

package comp_equ_hash_impl_interf;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;

interface Discountable {
    double getDiscount();
}
public abstract class Order implements Comparable<Order> {
    int id;
    String customer;
    double totalAmount;

    public Order(int id, String customer, double totalAmount) {
        this.id = id;
        this.customer = customer;
        this.totalAmount = totalAmount;
    }

    public int compareTo(Order other) {
        return Double.compare(this.totalAmount, other.totalAmount);
    }

    public boolean equals(Object o) {
        if (o == this) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Order order = (Order) o;
        return id == order.id;
    }

    public int hashCode() {
        return Double.hashCode(totalAmount);
    }

    public String toString() {
        return customer + " | " + totalAmount;
    }

    public static void main(String[] args) {
        ArrayList<Order> list = new ArrayList<>(Arrays.asList(
                new OrderOnline(1, "Alice", 150.00),
                new OrderOffline(2, "Bob", 200.00),
                new OrderOnline(3, "Charlie", 100.00),
                new OrderOnline(1, "Alice", 150.00)
        ));

        Collections.sort(list);
        System.out.println(list);
    }
}