Merge pull request #20 from leung018:order-service

Order service part 3

build.gradle

@@ -40,6 +40,7 @@ dependencies {
 	implementation "org.springframework.boot:spring-boot-starter-security"
 	implementation 'io.jsonwebtoken:jjwt-api:0.12.6'
 	implementation "com.google.guava:guava:33.3.1-jre"
+	implementation "org.springframework.retry:spring-retry"
 	runtimeOnly 'io.jsonwebtoken:jjwt-impl:0.12.6'
 	runtimeOnly 'io.jsonwebtoken:jjwt-jackson:0.12.6'
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'

src/main/java/com/leungcheng/spring_simple_backend/RetryConfig.java

@@ -0,0 +1,8 @@
+package com.leungcheng.spring_simple_backend;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.retry.annotation.EnableRetry;
+
+@EnableRetry
+@Configuration
+public class RetryConfig {}

src/main/java/com/leungcheng/spring_simple_backend/domain/Product.java

@@ -2,6 +2,7 @@
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.leungcheng.spring_simple_backend.validation.ObjectValidator;
+import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Id;
 import jakarta.persistence.Table;
@@ -71,6 +72,7 @@ public Builder toBuilder() {
 
   @NotBlank private String name;
 
+  @Column(precision = 19, scale = 5)
   @Min(0)
   private BigDecimal price;
 

src/main/java/com/leungcheng/spring_simple_backend/domain/User.java

@@ -75,6 +75,7 @@ public User.Builder toBuilder() {
   @NotBlank private String password;
 
   @Min(0)
+  @Column(precision = 19, scale = 10)
   private BigDecimal balance;
 
   @Override

src/main/java/com/leungcheng/spring_simple_backend/domain/order/OrderService.java

@@ -8,35 +8,34 @@
 import java.math.BigDecimal;
 import java.util.Map;
 import java.util.Optional;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.retry.annotation.Retryable;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Isolation;
 import org.springframework.transaction.annotation.Transactional;
 
 @Service
 public class OrderService {
-  private final UserRepository userRepository;
-  private final ProductRepository productRepository;
-  private final OrderRepository orderRepository;
-
-  public OrderService(
-      UserRepository userRepository,
-      ProductRepository productRepository,
-      OrderRepository orderRepository) {
-    this.userRepository = userRepository;
-    this.productRepository = productRepository;
-    this.orderRepository = orderRepository;
+  private @Autowired UserRepository userRepository;
+  private @Autowired ProductRepository productRepository;
+  private @Autowired OrderRepository orderRepository;
+
+  public static class CreateOrderException extends IllegalArgumentException {
+    public CreateOrderException(String message) {
+      super(message);
+    }
   }
 
+  @Retryable(noRetryFor = CreateOrderException.class)
   @Transactional(isolation = Isolation.SERIALIZABLE)
   public Order createOrder(String buyerUserId, PurchaseItems purchaseItems) {
     User buyer =
-        getUser(buyerUserId)
-            .orElseThrow(() -> new IllegalArgumentException("Buyer does not exist"));
+        getUser(buyerUserId).orElseThrow(() -> new CreateOrderException("Buyer does not exist"));
 
     BigDecimal totalCost = processPurchaseItems(purchaseItems);
 
     if (buyer.getBalance().compareTo(totalCost) < 0) {
-      throw new IllegalArgumentException("Insufficient balance");
+      throw new CreateOrderException("Insufficient balance");
     }
     saveNewBalance(buyer, buyer.getBalance().subtract(totalCost));
 
@@ -60,7 +59,7 @@ private Order addNewOrder(String buyerUserId, PurchaseItems purchaseItems) {
   private BigDecimal processPurchaseItems(PurchaseItems purchaseItems) {
     ImmutableMap<String, Integer> productIdToQuantity = purchaseItems.getProductIdToQuantity();
     if (productIdToQuantity.isEmpty()) {
-      throw new IllegalArgumentException("Purchase items cannot be empty");
+      throw new CreateOrderException("Purchase items cannot be empty");
     }
 
     BigDecimal totalCost = BigDecimal.ZERO;
@@ -80,7 +79,7 @@ private BigDecimal processPurchaseItems(PurchaseItems purchaseItems) {
 
   private void reduceProductStock(Product product, int purchaseQuantity) {
     if (purchaseQuantity > product.getQuantity()) {
-      throw new IllegalArgumentException("Insufficient stock for product: " + product.getId());
+      throw new CreateOrderException("Insufficient stock for product: " + product.getId());
     }
     int newQuantity = product.getQuantity() - purchaseQuantity;
     Product updatedProduct = product.toBuilder().quantity(newQuantity).build();
@@ -97,7 +96,6 @@ private void addProfitToSeller(Product product, int purchaseQuantity) {
   private Product getProduct(String productId) {
     return productRepository
         .findById(productId)
-        .orElseThrow(
-            () -> new IllegalArgumentException("Product: " + productId + " does not exist"));
+        .orElseThrow(() -> new CreateOrderException("Product: " + productId + " does not exist"));
   }
 }

src/main/java/com/leungcheng/spring_simple_backend/domain/order/PurchaseItems.java

@@ -6,7 +6,7 @@
 
 @Embeddable
 public class PurchaseItems {
-  @ElementCollection
+  @ElementCollection(fetch = FetchType.EAGER)
   @CollectionTable(
       name = "purchase_items",
       joinColumns = {@JoinColumn(name = "order_id", referencedColumnName = "id")})

src/test/java/com/leungcheng/spring_simple_backend/domain/PrecisionTest.java

@@ -0,0 +1,34 @@
+package com.leungcheng.spring_simple_backend.domain;
+
+import static com.leungcheng.spring_simple_backend.testutil.CustomAssertions.assertBigDecimalEquals;
+import static com.leungcheng.spring_simple_backend.testutil.DefaultBuilders.productBuilder;
+import static com.leungcheng.spring_simple_backend.testutil.DefaultBuilders.userBuilder;
+
+import java.math.BigDecimal;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class PrecisionTest {
+  private @Autowired ProductRepository productRepository;
+  private @Autowired UserRepository userRepository;
+
+  @Test
+  void shouldProductKeepPrecisionAfterSavingToRepository() {
+    Product product = productBuilder().price(new BigDecimal("123456.78912")).build();
+    productRepository.save(product);
+    Product savedProduct = productRepository.findById(product.getId()).orElseThrow();
+
+    assertBigDecimalEquals(product.getPrice(), savedProduct.getPrice());
+  }
+
+  @Test
+  void shouldUserKeepPrecisionAfterSavingToRepository() {
+    User user = userBuilder().balance(new BigDecimal("123456.78912")).build();
+    userRepository.save(user);
+    User savedUser = userRepository.findById(user.getId()).orElseThrow();
+
+    assertBigDecimalEquals(user.getBalance(), savedUser.getBalance());
+  }
+}

src/test/java/com/leungcheng/spring_simple_backend/domain/ProductTest.java

@@ -1,5 +1,6 @@
 package com.leungcheng.spring_simple_backend.domain;
 
+import static com.leungcheng.spring_simple_backend.testutil.DefaultBuilders.productBuilder;
 import static org.junit.jupiter.api.Assertions.*;
 
 import com.leungcheng.spring_simple_backend.validation.ObjectValidator;
@@ -8,14 +9,6 @@
 
 class ProductTest {
 
-  private static Product.Builder productBuilder() {
-    return new Product.Builder()
-        .name("Default Product")
-        .price(new BigDecimal("0.1"))
-        .userId("user_01")
-        .quantity(1);
-  }
-
   @Test
   void shouldCreateProduct() {
     Product product =

src/test/java/com/leungcheng/spring_simple_backend/domain/UserTest.java

@@ -1,19 +1,13 @@
 package com.leungcheng.spring_simple_backend.domain;
 
+import static com.leungcheng.spring_simple_backend.testutil.DefaultBuilders.userBuilder;
 import static org.junit.jupiter.api.Assertions.*;
 
 import com.leungcheng.spring_simple_backend.validation.ObjectValidator;
 import java.math.BigDecimal;
 import org.junit.jupiter.api.Test;
 
 class UserTest {
-  private static User.Builder userBuilder() {
-    return new User.Builder()
-        .username("default_user")
-        .password("default_password")
-        .balance(new BigDecimal("1.0"));
-  }
-
   @Test
   void shouldCreateUser() {
     User user =