BAEL-2354 - An Introduction to the Event Notification Model in CDI 2.0 (#5685)

* Initial Commit

* Update pom.xml

* Update pom.xml

* Update LowercaseTextServiceUnitTest.java

* Update UppercaseTextServiceUnitTest.java

* Delete TextApplication.java

* Update source files

* Update BootstrappingApplication.java

* Add AnotherSimpleEventObserver class

* Rename event classes

* Update ExampleEventSource.java

* Update UppercaseTextService.java

* Delete TextService.java

* Delete LowercaseTextService.java

* Delete LowercaseTextServiceUnitTest.java

* Delete UppercaseTextServiceUnitTest.java

* Fixed text service unit test

* Update TextService.java

cdi/src/main/java/com/baeldung/cdi2observers/application/BootstrappingApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.cdi.cdi2observers.application;
+
+import com.baeldung.cdi.cdi2observers.events.ExampleEvent;
+import javax.enterprise.inject.se.SeContainer;
+import javax.enterprise.inject.se.SeContainerInitializer;
+
+public class BootstrappingApplication {
+    
+    public static void main(String... args) {
+        SeContainerInitializer containerInitializer = SeContainerInitializer.newInstance();
+        try (SeContainer container = containerInitializer.initialize()) {
+            container.getBeanManager().fireEvent(new ExampleEvent("Welcome to Baeldung!"));
+        }
+    }
+}

cdi/src/main/java/com/baeldung/cdi2observers/events/ExampleEvent.java

@@ -0,0 +1,14 @@
+package com.baeldung.cdi.cdi2observers.events;
+
+public class ExampleEvent {
+    
+   private final String eventMessage;
+
+    public ExampleEvent(String eventMessage) {
+        this.eventMessage = eventMessage;
+    }
+    
+    public String getEventMessage() {
+        return eventMessage;
+    }
+}

cdi/src/main/java/com/baeldung/cdi2observers/events/ExampleEventSource.java

@@ -0,0 +1,14 @@
+package com.baeldung.cdi.cdi2observers.events;
+
+import javax.enterprise.event.Event;
+import javax.inject.Inject;
+
+public class ExampleEventSource {
+    
+    @Inject
+    Event<ExampleEvent> exampleEvent;
+    
+    public void fireEvent() {
+        exampleEvent.fireAsync(new ExampleEvent("Welcome to Baeldung!"));
+    }   
+}

cdi/src/main/java/com/baeldung/cdi2observers/observers/AnotherExampleEventObserver.java

@@ -0,0 +1,12 @@
+package com.baeldung.cdi.cdi2observers.observers;
+
+import com.baeldung.cdi.cdi2observers.events.ExampleEvent;
+import javax.annotation.Priority;
+import javax.enterprise.event.Observes;
+
+public class AnotherExampleEventObserver {
+    
+    public String onEvent(@Observes @Priority(2) ExampleEvent event) {
+        return event.getEventMessage();
+    }   
+}

cdi/src/main/java/com/baeldung/cdi2observers/observers/ExampleEventObserver.java

@@ -0,0 +1,13 @@
+package com.baeldung.cdi.cdi2observers.observers;
+
+import com.baeldung.cdi.cdi2observers.events.ExampleEvent;
+import com.baeldung.cdi.cdi2observers.services.TextService;
+import javax.annotation.Priority;
+import javax.enterprise.event.Observes;
+
+public class ExampleEventObserver {
+    
+    public String onEvent(@Observes @Priority(1) ExampleEvent event, TextService textService) {
+        return textService.parseText(event.getEventMessage());
+    } 
+}

cdi/src/main/java/com/baeldung/cdi2observers/services/TextService.java

@@ -0,0 +1,8 @@
+package com.baeldung.cdi.cdi2observers.services;
+
+public class TextService {
+
+    public String parseText(String text) {
+        return text.toUpperCase();
+    }
+}

cdi/src/test/java/com/baeldung/test/cdi2observers/tests/TextServiceUnitTest.java

@@ -0,0 +1,14 @@
+package com.baeldung.cdi.cdi2observers.tests;
+
+import com.baeldung.cdi.cdi2observers.services.TextService;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class TextServiceUnitTest {
+
+    @Test
+    public void givenTextServiceInstance_whenCalledparseText_thenCorrect() {
+        TextService textService = new TextService();
+        assertThat(textService.parseText("Baeldung")).isEqualTo("BAELDUNG");
+    }
+}