chore: refactor Payment and PaymentCounter to use UUID, add PaymentCounterService to track payment outcomes

Author: otaviojava

src/main/java/com/acme/payment/Payment.java

@@ -16,7 +16,7 @@
 public class Payment {
 
     @Id
-    private String id;
+    private UUID id;
 
     @Column
     private BigDecimal amount;
@@ -31,13 +31,13 @@ public class Payment {
     }
 
     Payment(Product product, BigDecimal amount, PaymentStatus status) {
-        this.id = UUID.randomUUID().toString();
+        this.id = UUID.randomUUID();
         this.amount = amount;
         this.status = status;
         this.product = product;
     }
 
-    public String getId() {
+    public UUID getId() {
         return id;
     }
 
@@ -54,6 +54,10 @@ public int hashCode() {
         return Objects.hashCode(id);
     }
 
+    public Product getProduct() {
+        return product;
+    }
+
     @Override
     public String toString() {
         return "Payment{" +

src/main/java/com/acme/stock/PaymentCounter.java

@@ -7,35 +7,37 @@
 import jakarta.nosql.Entity;
 import jakarta.nosql.Id;
 
+import java.util.UUID;
+
 @Entity
 @JsonbVisibility(JsonFieldStrategy.class)
 public class PaymentCounter {
 
     @Id
-    private String productCode;
+    private UUID productCode;
 
     @Column
     private Product product;
 
     @Column
-    private int successfulPayments;
+    int successfulPayments;
 
     @Column
-    private int failedPayments;
+    int failedPayments;
 
-    public String getProductCode() {
-        return productCode;
+    PaymentCounter(Product product) {
+        this.productCode = product.code();
+        this.product = product;
     }
 
-    public Product getProduct() {
-        return product;
+    PaymentCounter() {
     }
 
-    public int getSuccessfulPayments() {
-        return successfulPayments;
+    public void failedPayments() {
+        this.failedPayments++;
     }
 
-    public int getFailedPayments() {
-        return failedPayments;
+    public void successfulPayments() {
+        this.successfulPayments++;
     }
 }

src/main/java/com/acme/stock/PaymentCounterRepository.java

@@ -3,6 +3,8 @@
 import jakarta.data.repository.BasicRepository;
 import jakarta.data.repository.Repository;
 
+import java.util.UUID;
+
 @Repository
-public interface PaymentCounterRepository extends BasicRepository<PaymentCounter, String> {
+public interface PaymentCounterRepository extends BasicRepository<PaymentCounter, UUID> {
 }

src/main/java/com/acme/stock/PaymentCounterService.java

@@ -0,0 +1,47 @@
+package com.acme.stock;
+
+import com.acme.Product;
+import com.acme.payment.Payment;
+import com.acme.payment.PaymentErrorEvent;
+import com.acme.payment.PaymentSuccessEvent;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.event.Observes;
+import jakarta.inject.Inject;
+
+import java.util.logging.Logger;
+
+@ApplicationScoped
+public class PaymentCounterService {
+
+    private static final Logger LOGGER = Logger.getLogger(PaymentCounterService.class.getName());
+
+    private final PaymentCounterRepository repository;
+
+    @Inject
+    PaymentCounterService(PaymentCounterRepository repository) {
+        this.repository = repository;
+    }
+
+    PaymentCounterService() {
+        this.repository = null;
+    }
+
+    void success(@Observes PaymentSuccessEvent event) {
+        LOGGER.info("Payment successful, incrementing counter");
+        Payment payment = event.payment();
+        Product product = payment.getProduct();
+        PaymentCounter counter = repository.findById(payment.getProduct().code()).orElseGet(() -> new PaymentCounter(product));
+        counter.successfulPayments();
+        repository.save(counter);
+    }
+
+
+    void success(@Observes PaymentErrorEvent event) {
+        LOGGER.info("Payment failed, incrementing counter");
+        Payment payment = event.payment();
+        Product product = payment.getProduct();
+        PaymentCounter counter = repository.findById(payment.getProduct().code()).orElseGet(() -> new PaymentCounter(product));
+        counter.failedPayments();
+        repository.save(counter);
+    }
+}