Implement new inter-bean-dependencies exercise

Author: tboychuk

inter-bean-dependencies/README.MD

@@ -0,0 +1,21 @@
+# <img src="https://raw.githubusercontent.com/bobocode-projects/resources/master/image/logo_transparent_background.png" height=50/>Inter-bean dependencies exercise :muscle:
+Improve your *Spring ApplicationContext* Java configuration skills
+### Task
+The task is to **refactor Java configuration class `RootConfig`, in order to properly use Inter-bean dependencies.** 
+Your job is to follow the instructions in the *todo* section and **implement 
+a proper configuration.**  
+
+To verify your configuration, run `RootConfigContextTest.java` and `RootConfigHacksTest.java`
+
+ 
+### Pre-conditions :heavy_exclamation_mark:
+You're supposed to be familiar with *Spring IoC* and *Dependency injection* and Proxy pattern
+
+### How to start :question:
+* Just clone the repository and start implementing the **todo** section, verify your changes by running tests
+* If you don't have enough knowledge about this domain, check out the [links below](#related-materials-information_source)
+* Don't worry if you got stuck, checkout the **exercise/completed** branch and see the final implementation
+ 
+### Related materials :information_source:
+ * [Injecting Inter-bean Dependencies](https://docs.spring.io/spring/docs/5.1.9.RELEASE/spring-framework-reference/core.html#beans-java-injecting-dependencies) <img src="https://spring.io/img/homepage/icon-spring-framework.svg" height=15/>
+

inter-bean-dependencies/pom.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>spring-framework-exercises</artifactId>
+        <groupId>com.bobocode</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>bean-configuration-exercise</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.bobocode</groupId>
+            <artifactId>spring-framework-exercises-util</artifactId>
+            <version>1.0-SNAPSHOT</version>
+        </dependency>
+    </dependencies>
+</project>

inter-bean-dependencies/src/main/java/com/bobocode/config/RootConfig.java

@@ -0,0 +1,30 @@
+package com.bobocode.config;
+
+import com.bobocode.TestDataGenerator;
+import com.bobocode.dao.AccountDao;
+import com.bobocode.dao.impl.FakeAccountDao;
+import com.bobocode.service.AccountService;
+import org.springframework.context.annotation.Bean;
+import org.springframework.stereotype.Component;
+
+/**
+ * todo: Refactor {@link RootConfig} in order to user inter-bean dependencies properly.
+ */
+@Component
+public final class RootConfig {
+
+    @Bean
+    public AccountService accountService() {
+        return new AccountService(fakeAccountDao());
+    }
+
+    @Bean
+    public final AccountDao fakeAccountDao() {
+        return new FakeAccountDao(dataGenerator());
+    }
+
+    @Bean
+    private TestDataGenerator dataGenerator() {
+        return new TestDataGenerator();
+    }
+}

inter-bean-dependencies/src/main/java/com/bobocode/dao/AccountDao.java

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+package com.bobocode.dao;
+
+import com.bobocode.model.Account;
+
+public interface AccountDao {
+    Account findById(Long id);
+}

inter-bean-dependencies/src/main/java/com/bobocode/dao/impl/FakeAccountDao.java

@@ -0,0 +1,20 @@
+package com.bobocode.dao.impl;
+
+import com.bobocode.TestDataGenerator;
+import com.bobocode.dao.AccountDao;
+import com.bobocode.model.Account;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public class FakeAccountDao implements AccountDao {
+    private final TestDataGenerator dataGenerator;
+
+    @Override
+    public Account findById(Long id) {
+        Account account = dataGenerator.generateAccount();
+        account.setId(id);
+        return account;
+    }
+}

inter-bean-dependencies/src/main/java/com/bobocode/service/AccountService.java

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+package com.bobocode.service;
+
+import com.bobocode.dao.AccountDao;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public class AccountService {
+    private final AccountDao accountDao;
+
+}

inter-bean-dependencies/src/test/java/com/bobocode/RootConfigContextTest.java

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+package com.bobocode;
+
+import com.bobocode.config.RootConfig;
+import com.bobocode.dao.impl.FakeAccountDao;
+import com.bobocode.service.AccountService;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+
+@SpringJUnitConfig(classes = RootConfig.class)
+class RootConfigContextTest {
+
+    @Autowired
+    private AccountService accountService;
+
+    @Autowired
+    private FakeAccountDao accountDao;
+
+    @Autowired
+    private TestDataGenerator dataGenerator;
+
+    @Test
+    void dataGeneratorShouldHaveScopeSingleton() {
+        assertThat(accountDao.getDataGenerator()).isEqualTo(dataGenerator);
+    }
+
+    @Test
+    void accountDaoShouldHaveScopeSingleton() {
+        assertThat(accountService.getAccountDao()).isEqualTo(accountDao);
+    }
+}

inter-bean-dependencies/src/test/java/com/bobocode/RootConfigHacksTest.java

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+package com.bobocode;
+
+import com.bobocode.config.RootConfig;
+import com.bobocode.dao.impl.FakeAccountDao;
+import com.bobocode.service.AccountService;
+import org.junit.jupiter.api.Test;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Import;
+import org.springframework.stereotype.Component;
+import org.springframework.stereotype.Service;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class RootConfigHacksTest {
+
+    @Test
+    void rootConfigShouldNotUseComponentScan() {
+        ComponentScan componentScan = RootConfig.class.getAnnotation(ComponentScan.class);
+
+        assertThat(componentScan).isNull();
+    }
+
+    @Test
+    void rootConfigShouldNotImportOtherConfigs() {
+        Import importAnnotation = RootConfig.class.getAnnotation(Import.class);
+
+        assertThat(importAnnotation).isNull();
+    }
+
+    @Test
+    void accountServiceBeanShouldBeConfiguredExplicitly() {
+        Annotation[] annotations = AccountService.class.getAnnotations();
+        List<Class> annotationClasses = Stream.of(annotations).map(Annotation::annotationType).collect(Collectors.toList());
+
+        assertThat(annotationClasses).doesNotContain(Component.class, Service.class);
+    }
+
+    @Test
+    void fakeAccountDaoBeanShouldBeConfiguredExplicitly() {
+        Annotation[] annotations = FakeAccountDao.class.getAnnotations();
+        List<Class> annotationClasses = Stream.of(annotations).map(Annotation::annotationType).collect(Collectors.toList());
+
+        assertThat(annotationClasses).doesNotContain(Component.class, Service.class);
+    }
+
+    @Test
+    void rootConfigShouldUseInterBeanDependencies() {
+        Method[] methods = RootConfig.class.getDeclaredMethods();
+
+        assertThat(methods).noneMatch(method -> method.getParameterCount() > 0);
+    }
+}

pom.xml

@@ -15,6 +15,7 @@
         <module>account-jsp</module>
         <module>account-rest-api</module>
         <module>transactional-user-service</module>
+        <module>inter-bean-dependencies</module>
     </modules>
     <packaging>pom</packaging>
 
@@ -78,6 +79,12 @@
             <artifactId>slf4j-simple</artifactId>
             <version>1.7.24</version>
         </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.13.2</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>