BAEL-7547: testing spring events

spring-boot-modules/spring-boot-libraries-3/src/main/java/com/baeldung/springmodulith/application/events/orders/Order.java

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+package com.baeldung.springmodulith.application.events.orders;
+
+import java.time.Instant;
+import java.util.List;
+
+record Order(String id, String customerId, List<String> productIds, Instant timestamp) {
+
+	public Order(String customerId, List<String> productIds) {
+		this(null, customerId, productIds, Instant.now());
+	}
+
+}

spring-boot-modules/spring-boot-libraries-3/src/main/java/com/baeldung/springmodulith/application/events/orders/OrderCompletedEvent.java

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+package com.baeldung.springmodulith.application.events.orders;
+
+import java.time.Instant;
+
+public record OrderCompletedEvent(String orderId, String customerId, Instant time) {
+}

spring-boot-modules/spring-boot-libraries-3/src/main/java/com/baeldung/springmodulith/application/events/orders/OrderRepository.java

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+package com.baeldung.springmodulith.application.events.orders;
+
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+
+@Component
+class OrderRepository {
+	private final List<Order> orders = new ArrayList<>();
+
+	public Order save(Order order) {
+		order = new Order(UUID.randomUUID().toString(), order.customerId(), order.productIds(), order.timestamp());
+		orders.add(order);
+		return order;
+	}
+
+	public List<Order> ordersByCustomer(String customerId) {
+		return orders.stream()
+			.filter(it -> it.customerId().equals(customerId))
+			.toList();
+	}
+
+}

spring-boot-modules/spring-boot-libraries-3/src/main/java/com/baeldung/springmodulith/application/events/orders/OrderService.java

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+package com.baeldung.springmodulith.application.events.orders;
+
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.stereotype.Service;
+
+import java.util.Arrays;
+
+@Service
+public class OrderService {
+
+	private final OrderRepository repository;
+	private final ApplicationEventPublisher eventPublisher;
+
+	public OrderService(OrderRepository orders, ApplicationEventPublisher eventsPublisher) {
+		this.repository = orders;
+		this.eventPublisher = eventsPublisher;
+	}
+
+	public void placeOrder(String customerId, String... productIds) {
+		Order order = new Order(customerId, Arrays.asList(productIds));
+		// business logic to validate and place the order
+
+		Order savedOrder = repository.save(order);
+
+		OrderCompletedEvent event = new OrderCompletedEvent(savedOrder.id(), savedOrder.customerId(), savedOrder.timestamp());
+		eventPublisher.publishEvent(event);
+	}
+
+}

spring-boot-modules/spring-boot-libraries-3/src/main/java/com/baeldung/springmodulith/application/events/rewards/LoyalCustomersRepository.java

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+package com.baeldung.springmodulith.application.events.rewards;
+
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+@Component
+public class LoyalCustomersRepository {
+
+	private List<LoyalCustomer> customers = new ArrayList<>();
+
+	public Optional<LoyalCustomer> find(String customerId) {
+		return customers.stream()
+			.filter(it -> it.customerId().equals(customerId))
+			.findFirst();
+	}
+
+	public void awardPoints(String customerId, int points) {
+		var customer = find(customerId).orElseThrow();
+		customers.remove(customer);
+		customers.add(customer.addPoints(points));
+	}
+
+	public void save(String customerId) {
+		customers.add(new LoyalCustomer(customerId, 0));
+	}
+
+	public boolean isLoyalCustomer(String customerId) {
+		return find(customerId).isPresent();
+	}
+
+	public record LoyalCustomer(String customerId, int points) {
+
+		LoyalCustomer addPoints(int points) {
+			return new LoyalCustomer(customerId, this.points() + points);
+		}
+	}
+
+}

spring-boot-modules/spring-boot-libraries-3/src/main/java/com/baeldung/springmodulith/application/events/rewards/LoyaltyPointsService.java

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+package com.baeldung.springmodulith.application.events.rewards;
+
+import com.baeldung.springmodulith.application.events.orders.OrderCompletedEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Service;
+
+@Service
+public class LoyaltyPointsService {
+
+	public static final int ORDER_COMPLETED_POINTS = 10;
+	public static final int SING_UP_POINTS = 50;
+	private final LoyalCustomersRepository loyalCustomers;
+
+	public LoyaltyPointsService(LoyalCustomersRepository loyalCustomers) {
+		this.loyalCustomers = loyalCustomers;
+	}
+
+	@EventListener
+	public void onOrderCompleted(OrderCompletedEvent event) {
+		if (loyalCustomers.find(event.customerId()).isEmpty()) {
+			loyalCustomers.save(event.customerId());
+			loyalCustomers.awardPoints(event.customerId(), SING_UP_POINTS);
+		}
+
+		loyalCustomers.awardPoints(event.customerId(), ORDER_COMPLETED_POINTS);
+	}
+
+}

spring-boot-modules/spring-boot-libraries-3/src/test/java/com/baeldung/springmodulith/application/events/ApplicationEventsTest.java

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+package com.baeldung.springmodulith.application.events;
+
+import com.baeldung.springmodulith.application.events.orders.OrderService;
+import com.baeldung.springmodulith.application.events.rewards.LoyalCustomersRepository;
+import com.baeldung.springmodulith.application.events.rewards.LoyalCustomersRepository.LoyalCustomer;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.ComponentScan;
+
+import java.util.Optional;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@SpringBootTest
+@ComponentScan(basePackages = "com.baeldung.springmodulith.application.events")
+public class ApplicationEventsTest {
+
+
+	@Autowired
+	OrderService orderService;
+
+	@Autowired
+	LoyalCustomersRepository loyalCustomers;
+
+	@Test
+	void whenNewCustomerCompletesAnOrder_thenHeReceivesSingUpPointsPlusOrderPoints() {
+		orderService.placeOrder("customer1", "product1", "product2");
+
+		Optional<LoyalCustomer> customer = loyalCustomers.find("customer1");
+
+		assertThat(customer).isPresent()
+				.get()
+				.extracting(LoyalCustomer::points)
+				.isEqualTo(50 + 10);
+	}
+
+}