Source Code for hexagonal architecture article.

patterns/hexagonal-design-pattern/.gitignore

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+/target/
+.settings/
+.classpath
+.project
+/bin/

patterns/hexagonal-design-pattern/pom.xml

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+<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">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>hexagonal-design-pattern</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>hexagonal-design-pattern</name>
+    <packaging>war</packaging>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>1.5.3.RELEASE</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>ma.glasnost.orika</groupId>
+            <artifactId>orika-core</artifactId>
+            <version>1.4.6</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-actuator</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <artifactId>maven-compiler-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <artifactId>maven-war-plugin</artifactId>
+                <configuration>
+                    <warSourceDirectory>WebContent</warSourceDirectory>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                        <configuration>
+                            <mainClass>com.baeldung.hexagonal.Application</mainClass>
+                            <outputDirectory>${project.basedir}/docker</outputDirectory>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+        </plugins>
+    </build>
+
+    <properties>
+        <tomcat.version>8.0.43</tomcat.version>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <java.version>1.8</java.version>
+    </properties>
+
+</project>

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/Application.java

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+package com.baeldung.hexagonal;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/adapter/controller/UserController.java

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+package com.baeldung.hexagonal.adapter.controller;
+
+import java.util.List;
+
+import com.baeldung.hexagonal.core.contract.UserService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.http.HttpStatus;
+import com.baeldung.hexagonal.core.contract.User;
+
+@RestController
+public class UserController {
+
+    @Autowired
+    private UserService userService;
+
+    @PostMapping("/users")
+    @ResponseStatus(HttpStatus.CREATED)
+    public void addUser(@RequestBody User user) {
+        userService.addUser(user);
+    }
+
+    @GetMapping("/users")
+    public List<User> getUsers() {
+        return userService.getUsers();
+    }
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/adapter/data/UserDataAdapter.java

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+package com.baeldung.hexagonal.adapter.data;
+
+import com.baeldung.hexagonal.core.contract.dto.UserDTO;
+import java.util.List;
+
+public interface UserDataAdapter {
+
+    void addUser(UserDTO user);
+
+    List<UserDTO> getUsers();
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/adapter/data/UserDataAdapterImpl.java

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+package com.baeldung.hexagonal.adapter.data;
+
+import com.baeldung.hexagonal.adapter.data.entity.UserEntity;
+import com.baeldung.hexagonal.adapter.data.mapper.ModelMapper;
+import com.baeldung.hexagonal.adapter.data.repository.UserRepository;
+import com.baeldung.hexagonal.core.contract.dto.UserDTO;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+import java.util.List;
+
+@Component
+public class UserDataAdapterImpl implements UserDataAdapter {
+
+    @Autowired
+    private UserRepository userRepository;
+
+    @Autowired
+    private ModelMapper modelMapper;
+
+    public void addUser(UserDTO user) {
+        userRepository.save(modelMapper.map(user, UserEntity.class));
+    }
+
+    public List<UserDTO> getUsers() {
+        return modelMapper.mapAsList(userRepository.findAll(), UserDTO.class);
+    }
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/adapter/data/entity/UserEntity.java

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+package com.baeldung.hexagonal.adapter.data.entity;
+
+import javax.persistence.*;
+
+@Entity(name = "user")
+@Table(name = "user")
+public class UserEntity {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private long id;
+
+    private String name;
+
+    public UserEntity() {
+    }
+
+    public UserEntity(long id, String name) {
+        super();
+        this.id = id;
+        this.name = name;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/adapter/data/mapper/ModelMapper.java

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+package com.baeldung.hexagonal.adapter.data.mapper;
+
+import com.baeldung.hexagonal.adapter.data.entity.UserEntity;
+import com.baeldung.hexagonal.core.contract.dto.UserDTO;
+import ma.glasnost.orika.CustomMapper;
+import ma.glasnost.orika.MapperFactory;
+import ma.glasnost.orika.MappingContext;
+import ma.glasnost.orika.impl.ConfigurableMapper;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ModelMapper extends ConfigurableMapper {
+
+    public void configure(MapperFactory factory) {
+        super.configure(factory);
+
+        factory.registerClassMap(factory.classMap(UserDTO.class, UserEntity.class)
+            .customize(new CustomMapper<UserDTO, UserEntity>() {
+                @Override
+                public void mapAtoB(UserDTO userDTO, UserEntity userEntity, MappingContext context) {
+                    userEntity.setId(userDTO.getId());
+                    userEntity.setName(userDTO.getName());
+                }
+            })
+            .byDefault()
+            .toClassMap());
+
+        factory.registerClassMap(factory.classMap(UserEntity.class, UserDTO.class)
+            .customize(new CustomMapper<UserEntity, UserDTO>() {
+                @Override
+                public void mapAtoB(UserEntity userEntity, UserDTO userDTO, MappingContext context) {
+                    userDTO.setId(userEntity.getId());
+                    userDTO.setName(userEntity.getName());
+                }
+            })
+            .byDefault()
+            .toClassMap());
+
+    }
+
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/adapter/data/repository/UserRepository.java

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+package com.baeldung.hexagonal.adapter.data.repository;
+
+import com.baeldung.hexagonal.adapter.data.entity.UserEntity;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface UserRepository extends JpaRepository<UserEntity, Long> {
+
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/config/PersistenceConfig.java

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+package com.baeldung.hexagonal.config;
+
+import javax.sql.DataSource;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabase;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
+
+@Configuration
+public class PersistenceConfig {
+
+    @Bean
+    public DataSource dataSource() {
+        EmbeddedDatabaseBuilder builder = new EmbeddedDatabaseBuilder();
+        EmbeddedDatabase db = builder.setType(EmbeddedDatabaseType.H2)
+            .addScript("mySchema.sql")
+            .addScript("myData.sql")
+            .build();
+        return db;
+    }
+
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/core/contract/User.java

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+package com.baeldung.hexagonal.core.contract;
+
+public class User {
+
+    private long id;
+
+    private String name;
+
+    public User() {
+    }
+
+    public User(long id, String name) {
+        super();
+        this.id = id;
+        this.name = name;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/core/contract/UserService.java

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+package com.baeldung.hexagonal.core.contract;
+
+import java.util.List;
+
+public interface UserService {
+
+    void addUser(User user);
+
+    List<User> getUsers();
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/core/contract/dto/UserDTO.java

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+package com.baeldung.hexagonal.core.contract.dto;
+
+public class UserDTO {
+
+    private long id;
+
+    private String name;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/core/mapper/CoreModelMapper.java

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+package com.baeldung.hexagonal.core.mapper;
+
+import com.baeldung.hexagonal.core.contract.dto.UserDTO;
+import com.baeldung.hexagonal.core.contract.User;
+import ma.glasnost.orika.CustomMapper;
+import ma.glasnost.orika.MapperFactory;
+import ma.glasnost.orika.MappingContext;
+import ma.glasnost.orika.impl.ConfigurableMapper;
+import org.springframework.stereotype.Component;
+
+@Component
+public class CoreModelMapper extends ConfigurableMapper {
+
+    public void configure(MapperFactory factory) {
+        super.configure(factory);
+
+        factory.registerClassMap(factory.classMap(UserDTO.class, User.class)
+            .customize(new CustomMapper<UserDTO, User>() {
+                @Override
+                public void mapAtoB(UserDTO userDTO, User user, MappingContext context) {
+                    user.setId(userDTO.getId());
+                    user.setName(userDTO.getName());
+                }
+            })
+            .byDefault()
+            .toClassMap());
+
+        factory.registerClassMap(factory.classMap(User.class, UserDTO.class)
+            .customize(new CustomMapper<User, UserDTO>() {
+                @Override
+                public void mapAtoB(User user, UserDTO userDTO, MappingContext context) {
+                    userDTO.setId(user.getId());
+                    userDTO.setName(user.getName());
+                }
+            })
+            .byDefault()
+            .toClassMap());
+
+    }
+
+}

patterns/hexagonal-design-pattern/src/main/java/com/baeldung/hexagonal/core/service/UserServiceImpl.java

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+package com.baeldung.hexagonal.core.service;
+
+import com.baeldung.hexagonal.adapter.data.UserDataAdapter;
+import com.baeldung.hexagonal.core.contract.UserService;
+import com.baeldung.hexagonal.core.contract.dto.UserDTO;
+import com.baeldung.hexagonal.core.mapper.CoreModelMapper;
+import com.baeldung.hexagonal.core.contract.User;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import java.util.List;
+
+@Service
+public class UserServiceImpl implements UserService {
+
+    @Autowired
+    private UserDataAdapter userDataAdapter;
+
+    @Autowired
+    private CoreModelMapper coreModelMapper;
+
+    public void addUser(User user) {
+        userDataAdapter.addUser(coreModelMapper.map(user, UserDTO.class));
+    }
+
+    public List<User> getUsers() {
+        return coreModelMapper.mapAsList(userDataAdapter.getUsers(), User.class);
+    }
+}

patterns/hexagonal-design-pattern/src/main/resources/application.properties

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+server.port=8081
+server.contextPath=/hexagonaldesignapp
+logging.level.org.springframework.web: INFO
+
+spring.jpa.hibernate.ddl-auto=update

patterns/hexagonal-design-pattern/src/main/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

patterns/hexagonal-design-pattern/src/main/resources/myData.sql

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+insert into user(name) values ('ana');

patterns/hexagonal-design-pattern/src/main/resources/mySchema.sql

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+create table user(id int identity primary key, name varchar(30));

patterns/hexagonal-design-pattern/src/test/java/com/baeldung/hexagonal/test/UserControllerTest.java

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+package com.baeldung.hexagonal.test;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.context.WebApplicationContext;
+
+import static org.hamcrest.Matchers.*;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
+
+import com.baeldung.hexagonal.Application;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = Application.class)
+@WebAppConfiguration
+public class UserControllerTest {
+
+    private static final String CONTENT_TYPE = "application/json;charset=UTF-8";
+
+    private MockMvc mockMvc;
+
+    @Autowired
+    private WebApplicationContext webApplicationContext;
+
+    @Before
+    public void setup() throws Exception {
+        this.mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext)
+            .build();
+    }
+
+    @Test
+    public void whenCreateGetUser_thenOk() throws Exception {
+        String userJson = "{\"name\":\"john\"}";
+
+        this.mockMvc.perform(post("/users").contentType(CONTENT_TYPE)
+            .content(userJson))
+            .andExpect(status().isCreated());
+
+        this.mockMvc.perform(get("/users"))
+            .andExpect(status().isOk())
+            .andExpect(content().contentType(CONTENT_TYPE))
+            .andExpect(jsonPath("$", hasSize(2)))
+            .andExpect(jsonPath("$[0].name", is("ana")))
+            .andExpect(jsonPath("$[1].name", is("john")));
+    }
+}

patterns/pom.xml

@@ -17,6 +17,7 @@
         <module>front-controller</module>
         <module>intercepting-filter</module>
         <module>design-patterns</module>
+        <module>hexagonal-design-pattern</module>
     </modules>
 
     <dependencyManagement>