Merge pull request #10560 from vishal1023/origin/BAEL-4785

Origin/bael 4785

spring-core-5/src/main/java/com/baeldung/springbean/naming/component/Animal.java

@@ -0,0 +1,5 @@
+package com.baeldung.springbean.naming.component;
+
+public interface Animal {
+    String name();
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/component/Cat.java

@@ -0,0 +1,14 @@
+package com.baeldung.springbean.naming.component;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Component;
+
+@Component
+@Qualifier("cat")
+public class Cat implements Animal {
+
+    @Override
+    public String name() {
+        return "Cat";
+    }
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/component/CustomComponent.java

@@ -0,0 +1,7 @@
+package com.baeldung.springbean.naming.component;
+
+import org.springframework.stereotype.Component;
+
+@Component("myBean")
+public class CustomComponent {
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/component/Dog.java

@@ -0,0 +1,13 @@
+package com.baeldung.springbean.naming.component;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Component;
+
+@Component
+@Qualifier("dog")
+public class Dog implements Animal {
+    @Override
+    public String name() {
+        return "Dog";
+    }
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/configuration/AuditConfiguration.java

@@ -0,0 +1,14 @@
+package com.baeldung.springbean.naming.configuration;
+
+import com.baeldung.springbean.naming.service.AuditService;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class AuditConfiguration {
+
+    @Bean
+    public AuditService audit() {
+        return new AuditService();
+    }
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/configuration/MyConfiguration.java

@@ -0,0 +1,19 @@
+package com.baeldung.springbean.naming.configuration;
+
+import com.baeldung.springbean.naming.component.CustomComponent;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration("configuration")
+public class MyConfiguration {
+
+    @Bean("qualifierComponent")
+    public CustomComponent component() {
+        return new CustomComponent();
+    }
+
+    @Bean("beanComponent")
+    public CustomComponent myComponent() {
+        return new CustomComponent();
+    }
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/controller/MessagingController.java

@@ -0,0 +1,12 @@
+package com.baeldung.springbean.naming.controller;
+
+import com.baeldung.springbean.naming.service.MessagingService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Controller;
+
+@Controller
+public class MessagingController {
+
+    @Autowired
+    private MessagingService service;
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/service/AuditService.java

@@ -0,0 +1,4 @@
+package com.baeldung.springbean.naming.service;
+
+public class AuditService {
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/service/LoggingService.java

@@ -0,0 +1,7 @@
+package com.baeldung.springbean.naming.service;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class LoggingService {
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/service/MessagingService.java

@@ -0,0 +1,4 @@
+package com.baeldung.springbean.naming.service;
+
+public interface MessagingService {
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/service/MessagingServiceImpl.java

@@ -0,0 +1,14 @@
+package com.baeldung.springbean.naming.service;
+
+import com.baeldung.springbean.naming.component.CustomComponent;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Service;
+
+@Service
+public class MessagingServiceImpl implements MessagingService {
+
+    @Autowired
+    @Qualifier("qualifierComponent")
+    private CustomComponent customComponent;
+}

spring-core-5/src/main/java/com/baeldung/springbean/naming/service/PetShow.java

@@ -0,0 +1,26 @@
+package com.baeldung.springbean.naming.service;
+
+import com.baeldung.springbean.naming.component.Animal;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Service;
+
+@Service
+public class PetShow {
+
+    @Autowired
+    @Qualifier("dog")
+    private Animal dog;
+
+    @Autowired
+    @Qualifier("cat")
+    private Animal cat;
+
+    public Animal getDog() {
+        return dog;
+    }
+
+    public Animal getCat() {
+        return cat;
+    }
+}

spring-core-5/src/test/java/com/baeldung/springbean/naming/SpringBeanNamingUnitTest.java

@@ -0,0 +1,65 @@
+package com.baeldung.springbean.naming;
+
+import com.baeldung.springbean.naming.component.Cat;
+import com.baeldung.springbean.naming.component.Dog;
+import com.baeldung.springbean.naming.service.PetShow;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+@ExtendWith(SpringExtension.class)
+public class SpringBeanNamingUnitTest {
+
+    private AnnotationConfigApplicationContext context;
+
+    @BeforeEach
+    void setUp() {
+        context = new AnnotationConfigApplicationContext();
+        context.scan("com.baeldung.springbean.naming");
+        context.refresh();
+    }
+
+    // To name a bean spring gets the class name and converts the first letter to lowercase.
+    // Default naming strategy of the spring bean which is using class level annotation
+
+    @Test
+    void givenLoggingServiceBeanIsCreated_whenThereIsNoValueProvided_thenBeanNameShouldBeDefaultName() {
+        assertNotNull(context.getBean("loggingService"));
+    }
+
+    // In this case, to name a bean spring gets the class name and converts the first letter to lowercase.
+    @Test
+    void givenAuditServiceBeanIsCreatedWithMethodLevelAnnotation_whenThereIsNoValueProvided_thenBeanNameShouldBeTheNameOfMethod() {
+        assertNotNull(context.getBean("audit"));
+    }
+
+    // spring will create the bean of type CustomComponent with the name "myBean".
+    // As we're explicitly giving the name to the bean, spring will use this name to refer to it.
+    @Test
+    void givenCustomComponentBeanIsCreate_whenThereIsCustomNameGivenToBean_thenBeanShouldBeIdentifiedByThatName() {
+        assertNotNull(context.getBean("myBean"));
+    }
+
+    @Test
+    void givenCustomComponentBeanIsCreated_whenCustomNameIsGivenOnMethodLevelAnnotation_thenBeanShouldBeIdentifiedByThatName() {
+        assertNotNull(context.getBean("beanComponent"));
+        assertNotNull(context.getBean("configuration"));
+        assertNotNull(context.getBean("qualifierComponent"));
+    }
+
+    @Test
+    void givenMultipleImplementationsOfAnimal_whenFieldIsInjectedWithQualifiedName_thenTheSpecificBeanShouldGetInjected() {
+        PetShow petShow = (PetShow) context.getBean("petShow");
+
+        assertNotNull(context.getBean("cat"));
+        assertNotNull(context.getBean("dog"));
+
+        assertThat(petShow.getCat().getClass()).isEqualTo(Cat.class);
+        assertThat(petShow.getDog().getClass()).isEqualTo(Dog.class);
+    }
+}