Product.java

package shop;

import java.math.BigDecimal;
import java.util.Objects;

public final class Product {
    private final String id;
    private final String name;
    private final BigDecimal unitPrice;

    public Product(String id, String name, BigDecimal unitPrice) {
        if (id == null || id.isBlank()) throw new IllegalArgumentException("id");
        if (name == null || name.isBlank()) throw new IllegalArgumentException("name");
        this.id = id;
        this.name = name;
        this.unitPrice = Objects.requireNonNull(unitPrice, "unitPrice");
        if (unitPrice.signum() < 0) throw new IllegalArgumentException("unitPrice måste vara >= 0");
    }

    public String id() {
        return id;
    }

    public String name() {
        return name;
    }

    public BigDecimal unitPrice() {
        return unitPrice;
    }
}