12 - CDI Events: Introduce Recipe Change Events

src/main/java/de/schulung/quarkus/recipes/domain/RecipesService.java

@@ -1,8 +1,11 @@
 package de.schulung.quarkus.recipes.domain;
 
+import de.schulung.quarkus.recipes.domain.events.RecipeCreatedEvent;
+import de.schulung.quarkus.recipes.domain.events.RecipeEvent;
 import de.schulung.quarkus.recipes.domain.model.Difficulty;
 import de.schulung.quarkus.recipes.domain.model.Recipe;
 import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.event.Event;
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 
@@ -15,6 +18,7 @@
 public class RecipesService {
 
   private final RecipesDao dao;
+  private final Event<RecipeEvent> eventPublisher;
 
   public Stream<Recipe> findAll() {
     return dao.findAll();
@@ -39,5 +43,7 @@ public void create(
     }
 
     dao.save(recipe);
+
+    eventPublisher.fire(new RecipeCreatedEvent(recipe));
   }
 }

src/main/java/de/schulung/quarkus/recipes/domain/events/RecipeCreatedEvent.java

@@ -0,0 +1,8 @@
+package de.schulung.quarkus.recipes.domain.events;
+
+import de.schulung.quarkus.recipes.domain.model.Recipe;
+
+public record RecipeCreatedEvent(
+  Recipe recipe
+) implements RecipeEvent {
+}

src/main/java/de/schulung/quarkus/recipes/domain/events/RecipeEvent.java

@@ -0,0 +1,4 @@
+package de.schulung.quarkus.recipes.domain.events;
+
+public interface RecipeEvent {
+}

src/main/java/de/schulung/quarkus/recipes/infrastructure/RecipeEventsLogger.java

@@ -0,0 +1,25 @@
+package de.schulung.quarkus.recipes.infrastructure;
+
+import de.schulung.quarkus.recipes.domain.events.RecipeCreatedEvent;
+import io.quarkus.arc.log.LoggerName;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.event.Observes;
+import org.jboss.logging.Logger;
+
+@ApplicationScoped
+public class RecipeEventsLogger {
+
+  @LoggerName("customer-events")
+  Logger log;
+
+  public void logRecipeCreatedEvent(
+    @Observes
+    RecipeCreatedEvent event
+  ) {
+    log.infov(
+      "Recipe created with id={0}",
+      event.recipe().getId()
+    );
+  }
+
+}

src/test/java/de/schulung/quarkus/recipes/infrastructure/RecipeEventsLoggerTests.java

@@ -0,0 +1,52 @@
+package de.schulung.quarkus.recipes.infrastructure;
+
+import de.schulung.quarkus.recipes.test.CaptureOutput;
+import de.schulung.quarkus.recipes.test.CaptureOutput.CapturedOutput;
+import io.quarkus.test.TestTransaction;
+import io.quarkus.test.junit.QuarkusTest;
+import io.restassured.http.ContentType;
+import org.junit.jupiter.api.Test;
+
+import static io.restassured.RestAssured.given;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@QuarkusTest
+@TestTransaction
+@CaptureOutput
+class RecipeEventsLoggerTests {
+
+  @Test
+  void whenCreateRecipe_thenLogEvent(CapturedOutput output) {
+    var response = given()
+      .contentType(ContentType.JSON)
+      .body("""
+        {
+          "name": "Tomato Soup",
+          "img": "/my-image",
+          "servings": 4,
+          "duration": 30,
+          "difficulty": "easy",
+          "ingredients": [
+            { "unit": "pieces", "quantity": 2.0, "name": "Tomato" }
+          ],
+          "preparation": "Boil tomatoes."
+        }
+        """)
+      .accept(ContentType.JSON)
+      .when()
+      .post("/recipes");
+    response
+      .then()
+      .statusCode(201)
+      .header("Location", is(notNullValue()));
+    var id = response.body().jsonPath().getString("id");
+
+    assertTrue(
+      output.toString().matches("(?si).*Recipe created.*" + id + ".*"),
+      "Expected log output to contain 'Recipe created' with id=" + id
+    );
+  }
+
+}

src/test/java/de/schulung/quarkus/recipes/test/CaptureOutput.java

@@ -0,0 +1,141 @@
+package de.schulung.quarkus.recipes.test;
+
+import org.jspecify.annotations.NonNull;
+import org.junit.jupiter.api.extension.*;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.text.MessageFormat;
+import java.util.function.Supplier;
+import java.util.logging.Handler;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+
+/**
+ * Annotation to enable capturing of output produced during test execution.
+ * <p>
+ * When applied to a test method or class, any output (such as log messages) produced
+ * during the test's execution is captured, allowing it to be accessed and verified.
+ * <p>
+ * This annotation works in conjunction with the {@link OutputCaptureExtension}, which
+ * handles the logic for capturing and providing access to the captured output.
+ * <p>
+ * The annotation can be applied at the test method or class level.
+ * <p>
+ * Target: {@link ElementType#METHOD}, {@link ElementType#TYPE}
+ * Retention: {@link RetentionPolicy#RUNTIME}
+ *
+ * @see OutputCaptureExtension
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({
+  ElementType.METHOD,
+  ElementType.TYPE
+})
+@ExtendWith(CaptureOutput.OutputCaptureExtension.class)
+public @interface CaptureOutput {
+
+  @SuppressWarnings("NullableProblems")
+  public record CapturedOutput(Supplier<String> output)
+    implements CharSequence {
+
+    @Override
+    public int length() {
+      return output.get().length();
+    }
+
+    @Override
+    public char charAt(int index) {
+      return output.get().charAt(index);
+    }
+
+    @Override
+    public CharSequence subSequence(int start, int end) {
+      return output.get().subSequence(start, end);
+    }
+
+    @Override
+    public String toString() {
+      return output.get();
+    }
+  }
+
+  class OutputCaptureExtension
+    implements BeforeEachCallback, AfterEachCallback, ParameterResolver {
+
+    private Handler handler;
+    private CapturedOutput capturedOutput;
+
+    @Override
+    public void beforeEach(
+      @NonNull
+      ExtensionContext context
+    ) {
+
+      final StringBuilder sb = new StringBuilder();
+      this.handler = new Handler() {
+
+        @Override
+        public void publish(LogRecord record) {
+          final var message = MessageFormat
+            .format(
+              record.getMessage(),
+              record.getParameters()
+            );
+          sb.append(message);
+        }
+
+        @Override
+        public void flush() {
+        }
+
+        @Override
+        public void close() throws SecurityException {
+        }
+      };
+      this.capturedOutput = new CapturedOutput(sb::toString);
+
+      Logger
+        .getLogger("")
+        .addHandler(this.handler);
+    }
+
+    @Override
+    public void afterEach(
+      @NonNull
+      ExtensionContext context
+    ) {
+      Logger
+        .getLogger("")
+        .removeHandler(this.handler);
+      this.handler = null;
+      this.capturedOutput = null;
+    }
+
+    @Override
+    public boolean supportsParameter(
+      ParameterContext parameterContext,
+      @NonNull
+      ExtensionContext context
+    ) {
+      return parameterContext
+        .getParameter()
+        .getType()
+        .equals(CapturedOutput.class);
+    }
+
+    @Override
+    public Object resolveParameter(
+      @NonNull
+      ParameterContext parameterContext,
+      @NonNull
+      ExtensionContext context
+    ) {
+      return this.capturedOutput;
+    }
+
+  }
+
+}