Add it again

model/src/main/java/eu/happycoders/shop/model/cart/Cart.java

@@ -8,6 +8,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * A shopping cart of a particular customer, containing several line items.
+ *
+ * @author Sven Woltmann
+ */
 public class Cart {
 
   private final CustomerId id; // cart ID = customer ID

model/src/main/java/eu/happycoders/shop/model/cart/CartLineItem.java

@@ -3,6 +3,11 @@
 import eu.happycoders.shop.model.money.Money;
 import eu.happycoders.shop.model.product.Product;
 
+/**
+ * A shopping cart line item with a product and quantity.
+ *
+ * @author Sven Woltmann
+ */
 public class CartLineItem {
 
   private final Product product;

model/src/main/java/eu/happycoders/shop/model/cart/NotEnoughItemsInStockException.java

@@ -1,5 +1,11 @@
 package eu.happycoders.shop.model.cart;
 
+/**
+ * An exception indicating that a customer wanted to add more items of a product to the cart than
+ * were available.
+ *
+ * @author Sven Woltmann
+ */
 public class NotEnoughItemsInStockException extends Exception {
 
   private final int itemsInStock;

model/src/main/java/eu/happycoders/shop/model/customer/CustomerId.java

@@ -1,5 +1,10 @@
 package eu.happycoders.shop.model.customer;
 
+/**
+ * A customer ID value object (enabling type-safety and validation).
+ *
+ * @author Sven Woltmann
+ */
 public record CustomerId(int value) {
 
   public CustomerId {

model/src/main/java/eu/happycoders/shop/model/money/Money.java

@@ -4,6 +4,11 @@
 import java.util.Currency;
 import java.util.Objects;
 
+/**
+ * A money value object consisting of a currency and an amount.
+ *
+ * @author Sven Woltmann
+ */
 public record Money(Currency currency, BigDecimal amount) {
 
   public static final Currency EUR = Currency.getInstance("EUR");

model/src/main/java/eu/happycoders/shop/model/product/Product.java

@@ -4,6 +4,11 @@
 import eu.happycoders.shop.model.cart.NotEnoughItemsInStockException;
 import eu.happycoders.shop.model.money.Money;
 
+/**
+ * A product listed in the shop.
+ *
+ * @author Sven Woltmann
+ */
 @SuppressWarnings("PMD.ImmutableField") // name, description, etc... should eventually be modifiable
 public class Product {
 

model/src/main/java/eu/happycoders/shop/model/product/ProductId.java

@@ -3,6 +3,11 @@
 import java.util.Objects;
 import java.util.concurrent.ThreadLocalRandom;
 
+/**
+ * A product ID value object (enabling type-safety and validation).
+ *
+ * @author Sven Woltmann
+ */
 public record ProductId(String value) {
 
   private static final String ALPHABET = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";