Port Round 2 to Java (OrderBook): 14 tests total green, START state preserved

2026-10-01 13:38:42 +01:00
parent f927998149
commit 2831b8c3f9
5 changed files with 259 additions and 0 deletions
@@ -0,0 +1,42 @@
+package orderbookdomain;
+
+import java.time.Instant;
+
+public class Order {
+
+    private final int id;
+    private final String customer;
+
+    private OrderStatus status;
+    private Instant finalizedAt;
+
+    Order(int id, String customer) {
+        this.id = id;
+        this.customer = customer;
+        this.status = OrderStatus.PENDING;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public String getCustomer() {
+        return customer;
+    }
+
+    public OrderStatus getStatus() {
+        return status;
+    }
+
+    public Instant getFinalizedAt() {
+        return finalizedAt;
+    }
+
+    void setStatus(OrderStatus status) {
+        this.status = status;
+    }
+
+    void setFinalizedAt(Instant finalizedAt) {
+        this.finalizedAt = finalizedAt;
+    }
+}
@@ -0,0 +1,81 @@
+package orderbookdomain;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class OrderBook {
+
+    private final Duration paymentWindow;
+    private final Map<Integer, Order> ordersById = new HashMap<>();
+    private int nextId = 1;
+
+    public OrderBook() {
+        this(Duration.ofDays(14));
+    }
+
+    public OrderBook(Duration paymentWindow) {
+        this.paymentWindow = paymentWindow;
+    }
+
+    public List<Order> getOrders() {
+        return List.copyOf(ordersById.values());
+    }
+
+    public Order openOrder(String customer) {
+        Order order = new Order(nextId++, customer);
+        ordersById.put(order.getId(), order);
+        return order;
+    }
+
+    public Order getOrder(int orderId) {
+        Order order = ordersById.get(orderId);
+        if (order == null) {
+            throw new IllegalStateException("Unknown order id " + orderId + ".");
+        }
+        return order;
+    }
+
+    public void finalizeOrder(int orderId, Instant finalizedAt) {
+        Order order = getOrder(orderId);
+        requireStatus(order, OrderStatus.PENDING, "finalize");
+        order.setStatus(OrderStatus.WAITING_FOR_PAYMENT);
+        order.setFinalizedAt(finalizedAt);
+    }
+
+    public void payOrder(int orderId, Instant paidAt) {
+        Order order = getOrder(orderId);
+        requireStatus(order, OrderStatus.WAITING_FOR_PAYMENT, "pay");
+        if (Duration.between(order.getFinalizedAt(), paidAt).compareTo(paymentWindow) > 0) {
+            order.setStatus(OrderStatus.CANCELLED);
+            throw new IllegalStateException(
+                "Payment for order " + orderId + " arrived after the payment window; the order was cancelled.");
+        }
+        order.setStatus(OrderStatus.FULFILLING);
+    }
+
+    public void shipOrder(int orderId) {
+        Order order = getOrder(orderId);
+        requireStatus(order, OrderStatus.FULFILLING, "ship");
+        order.setStatus(OrderStatus.DELIVERED);
+    }
+
+    public void cancelOrder(int orderId) {
+        Order order = getOrder(orderId);
+        if (order.getStatus() != OrderStatus.PENDING && order.getStatus() != OrderStatus.WAITING_FOR_PAYMENT) {
+            throw new IllegalStateException(
+                "Cannot cancel order " + orderId + " in status " + order.getStatus() + ".");
+        }
+        order.setStatus(OrderStatus.CANCELLED);
+    }
+
+    private static void requireStatus(Order order, OrderStatus expected, String action) {
+        if (order.getStatus() != expected) {
+            throw new IllegalStateException(
+                "Cannot " + action + " order " + order.getId() + " in status " + order.getStatus()
+                    + " (expected " + expected + ").");
+        }
+    }
+}
@@ -0,0 +1,9 @@
+package orderbookdomain;
+
+public enum OrderStatus {
+    PENDING,
+    WAITING_FOR_PAYMENT,
+    FULFILLING,
+    DELIVERED,
+    CANCELLED
+}