Add event for blog post created

src/main/java/de/sample/schulung/spring/blog/domain/BlogPost.java

@@ -5,13 +5,15 @@
 import lombok.Builder;
 import lombok.Getter;
 import lombok.Setter;
+import lombok.ToString;
 
 import java.time.LocalDateTime;
 import java.util.UUID;
 
 @Builder
 @Getter
 @Setter
+@ToString
 public class BlogPost {
 
   private UUID id;

src/main/java/de/sample/schulung/spring/blog/domain/BlogPostCreatedEvent.java

@@ -0,0 +1,7 @@
+package de.sample.schulung.spring.blog.domain;
+
+public record BlogPostCreatedEvent(
+  BlogPost blogPost
+) {
+
+}

src/main/java/de/sample/schulung/spring/blog/domain/BlogPostEventLogger.java

@@ -0,0 +1,16 @@
+package de.sample.schulung.spring.blog.domain;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+@Component
+@Slf4j
+public class BlogPostEventLogger {
+
+  @EventListener
+  void logBlogPostCreated(BlogPostCreatedEvent evt) {
+    log.debug("BlogPost created: {}", evt.blogPost());
+  }
+
+}

src/main/java/de/sample/schulung/spring/blog/domain/BlogPostService.java

@@ -2,6 +2,8 @@
 
 import jakarta.validation.Valid;
 import jakarta.validation.constraints.NotNull;
+import lombok.RequiredArgsConstructor;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Service;
 import org.springframework.validation.annotation.Validated;
 
@@ -14,9 +16,11 @@
 
 @Validated
 @Service
+@RequiredArgsConstructor
 public class BlogPostService {
 
   private final Map<UUID, BlogPost> blogPosts = new HashMap<>();
+  private final ApplicationEventPublisher eventPublisher;
 
   public long count() {
     return blogPosts.size();
@@ -37,6 +41,7 @@ public void create(@Valid @NotNull BlogPost blogPost) {
     blogPost.setId(id);
     blogPost.setTimestamp(LocalDateTime.now());
     this.blogPosts.put(id, blogPost);
+    this.eventPublisher.publishEvent(new BlogPostCreatedEvent(blogPost));
   }
 
 

src/main/resources/application.yml

@@ -1,2 +1,5 @@
 server:
   port: ${SERVER_PORT:9080}
+logging:
+  level:
+    de.sample.schulung.spring.blog.domain.BlogPostEventLogger: debug

src/test/java/de/sample/schulung/spring/blog/boundary/BlogPostControllerTests.java

@@ -3,6 +3,8 @@
 import de.sample.schulung.spring.blog.domain.BlogPostService;
 import org.junit.jupiter.api.Test;
 import org.mapstruct.factory.Mappers;
+import org.mockito.Mockito;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.http.HttpStatus;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -11,7 +13,8 @@ public class BlogPostControllerTests {
 
   @Test
   void shouldCreateBlogPostSuccessfully() {
-    final var service = new BlogPostService();
+    final var eventPublisher = Mockito.mock(ApplicationEventPublisher.class);
+    final var service = new BlogPostService(eventPublisher);
     final var mapper = Mappers.getMapper(BlogPostDtoMapper.class);
     final var controller = new BlogPostController(service, mapper);
     final var blogPost = new BlogPostDto();
@@ -27,6 +30,8 @@ void shouldCreateBlogPostSuccessfully() {
     assertThat(result.getBody().getTitle())
       .isEqualTo(blogPost.getTitle());
 
+    // TODO verify eventPublisher.publishEvent?
+
   }
 
 }

src/test/java/de/sample/schulung/spring/blog/domain/BlogPostEventsTests.java

@@ -0,0 +1,50 @@
+package de.sample.schulung.spring.blog.domain;
+
+import jakarta.validation.ConstraintViolationException;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.event.ApplicationEvents;
+import org.springframework.test.context.event.RecordApplicationEvents;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+@SpringBootTest
+@RecordApplicationEvents
+public class BlogPostEventsTests {
+
+  @Autowired
+  BlogPostService service;
+  @SuppressWarnings("SpringJavaInjectionPointsAutowiringInspection")
+  @Autowired
+  ApplicationEvents events;
+
+  @Test
+  void shouldPublishEventOnCreate() {
+    final var newBlogPost = BlogPost
+      .builder()
+      .title("test")
+      .content("test content with 10 chars")
+      .build();
+    service.create(newBlogPost);
+
+    assertThat(events.stream(BlogPostCreatedEvent.class))
+      .hasSize(1)
+      .first()
+      .extracting(BlogPostCreatedEvent::blogPost)
+      .isSameAs(newBlogPost);
+  }
+
+  @Test
+  void shouldNotPublishEventOnInvalidCreate() {
+    final var newBlogPost = BlogPost
+      .builder()
+      .content("test content with 10 chars")
+      .build();
+    assertThatThrownBy(() -> service.create(newBlogPost))
+      .isInstanceOf(ConstraintViolationException.class);
+    assertThat(events.stream(BlogPostCreatedEvent.class))
+      .isEmpty();
+  }
+}