Hexagonal Architecture with Spring Boot example

patterns/hexagonal-architecture-example/pom.xml

@@ -0,0 +1,72 @@
+<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung</groupId>
+	<artifactId>hexagonal-architecture-example</artifactId>
+	<version>1.0</version>
+	<name>hexagonal-architecture-example</name>
+	<description>Project for hexagonal architecture example in java</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-boot-2</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-2</relativePath>
+    </parent>
+
+	<properties>
+		<java.version>1.8</java.version>
+	</properties>
+
+	<dependencies>
+		<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>
+            <scope>runtime</scope>
+        </dependency>
+		
+		<dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+			<exclusions>
+				<exclusion>
+					<groupId>org.junit.vintage</groupId>
+					<artifactId>junit-vintage-engine</artifactId>
+				</exclusion>
+			</exclusions>
+		</dependency>
+		<dependency>
+			<groupId>org.mockito</groupId>
+			<artifactId>mockito-core</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/HexagonalArchitectureApplication.java

@@ -0,0 +1,26 @@
+package com.baeldung.pattern.hexagonal.architecture;
+
+import com.baeldung.pattern.hexagonal.architecture.adapters.persistence.CarRepository;
+import com.baeldung.pattern.hexagonal.architecture.application.domain.Car;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class HexagonalArchitectureApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(HexagonalArchitectureApplication.class, args);
+    }
+
+    @Bean
+    public CommandLineRunner bootstrapData(CarRepository carRepository) {
+        return (args) -> {
+            Car car = new Car();
+            car.setId(1L);
+            car.setInUse(false);
+            carRepository.save(car);
+        };
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/adapters/persistence/CarRepository.java

@@ -0,0 +1,28 @@
+package com.baeldung.pattern.hexagonal.architecture.adapters.persistence;
+
+import com.baeldung.pattern.hexagonal.architecture.application.domain.Car;
+import com.baeldung.pattern.hexagonal.architecture.application.port.outgoing.LoadCarPort;
+import com.baeldung.pattern.hexagonal.architecture.application.port.outgoing.SaveCarPort;
+import org.springframework.stereotype.Component;
+
+import java.util.Optional;
+
+@Component
+public class CarRepository implements LoadCarPort, SaveCarPort {
+
+    private SpringDataCarRepository springDataCarRepository;
+
+    public CarRepository(SpringDataCarRepository springDataCarRepository) {
+        this.springDataCarRepository = springDataCarRepository;
+    }
+
+    @Override
+    public Optional<Car> load(Long id) {
+        return springDataCarRepository.findById(id);
+    }
+
+    @Override
+    public void save(Car car) {
+        springDataCarRepository.save(car);
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/adapters/persistence/SpringDataCarRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.pattern.hexagonal.architecture.adapters.persistence;
+
+import com.baeldung.pattern.hexagonal.architecture.application.domain.Car;
+import org.springframework.data.repository.CrudRepository;
+
+public interface SpringDataCarRepository extends CrudRepository<Car, Long> {
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/adapters/web/CarController.java

@@ -0,0 +1,31 @@
+package com.baeldung.pattern.hexagonal.architecture.adapters.web;
+
+import com.baeldung.pattern.hexagonal.architecture.application.port.incoming.RentCarUseCase;
+import com.baeldung.pattern.hexagonal.architecture.application.port.incoming.ReturnRentalUseCase;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/car")
+public class CarController {
+
+    private final RentCarUseCase rentCarUseCase;
+    private final ReturnRentalUseCase returnRentalUseCase;
+
+    public CarController(RentCarUseCase rentCarUseCase, ReturnRentalUseCase returnRentalUseCase){
+        this.rentCarUseCase = rentCarUseCase;
+        this.returnRentalUseCase = returnRentalUseCase;
+    }
+
+    @PostMapping(value = "/{id}/rent")
+    void rent(@PathVariable final Long id) {
+        rentCarUseCase.rent(id);
+    }
+
+    @PostMapping(value = "/{id}/return-rental")
+    void returnRental(@PathVariable final Long id) {
+        returnRentalUseCase.returnRental(id);
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/application/domain/Car.java

@@ -0,0 +1,40 @@
+package com.baeldung.pattern.hexagonal.architecture.application.domain;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import lombok.AllArgsConstructor;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+@Entity
+public class Car {
+
+    @Id
+    private Long id;
+
+    private Boolean inUse;
+
+    public boolean rent() {
+        if(this.inUse) {
+            return false;
+        } else {
+            this.inUse = true;
+            return true;
+        }
+    }
+
+    public boolean returnRental() {
+        if(this.inUse) {
+            this.inUse = false;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    //getter and setters
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/application/port/incoming/RentCarUseCase.java

@@ -0,0 +1,5 @@
+package com.baeldung.pattern.hexagonal.architecture.application.port.incoming;
+
+public interface RentCarUseCase {
+    boolean rent(Long id);
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/application/port/incoming/ReturnRentalUseCase.java

@@ -0,0 +1,5 @@
+package com.baeldung.pattern.hexagonal.architecture.application.port.incoming;
+
+public interface ReturnRentalUseCase {
+    boolean returnRental(Long id);
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/application/port/outgoing/LoadCarPort.java

@@ -0,0 +1,9 @@
+package com.baeldung.pattern.hexagonal.architecture.application.port.outgoing;
+
+import com.baeldung.pattern.hexagonal.architecture.application.domain.Car;
+
+import java.util.Optional;
+
+public interface LoadCarPort {
+    Optional<Car> load(Long id);
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/application/port/outgoing/SaveCarPort.java

@@ -0,0 +1,7 @@
+package com.baeldung.pattern.hexagonal.architecture.application.port.outgoing;
+
+import com.baeldung.pattern.hexagonal.architecture.application.domain.Car;
+
+public interface SaveCarPort {
+    void save(Car car);
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/pattern/hexagonal/architecture/application/services/CarService.java

@@ -0,0 +1,48 @@
+package com.baeldung.pattern.hexagonal.architecture.application.services;
+
+import com.baeldung.pattern.hexagonal.architecture.application.domain.Car;
+import com.baeldung.pattern.hexagonal.architecture.application.port.incoming.RentCarUseCase;
+import com.baeldung.pattern.hexagonal.architecture.application.port.incoming.ReturnRentalUseCase;
+import com.baeldung.pattern.hexagonal.architecture.application.port.outgoing.LoadCarPort;
+import com.baeldung.pattern.hexagonal.architecture.application.port.outgoing.SaveCarPort;
+import org.springframework.stereotype.Service;
+
+import java.util.NoSuchElementException;
+
+@Service
+public class CarService implements RentCarUseCase, ReturnRentalUseCase {
+
+    private LoadCarPort loadCarPort;
+    private SaveCarPort saveCarPort;
+
+    public CarService(LoadCarPort loadCarPort, SaveCarPort saveCarPort) {
+        this.loadCarPort = loadCarPort;
+        this.saveCarPort = saveCarPort;
+    }
+
+    @Override
+    public boolean rent(Long id) {
+        Car car = loadCarPort.load(id).orElseThrow(NoSuchElementException::new);
+
+        boolean hasRent = car.rent();
+
+        if(hasRent) {
+            saveCarPort.save(car);
+        }
+
+        return hasRent;
+    }
+
+    @Override
+    public boolean returnRental(Long id) {
+        Car car = loadCarPort.load(id).orElseThrow(NoSuchElementException::new);
+
+        boolean hasReturned = car.returnRental();
+
+        if(hasReturned) {
+            saveCarPort.save(car);
+        }
+
+        return hasReturned;
+    }
+}

patterns/hexagonal-architecture-example/src/main/resources/application.properties

@@ -0,0 +1 @@
+

patterns/hexagonal-architecture-example/src/test/java/com/baeldung/hexagonal/architecture/CarServiceUnitTest.java

@@ -0,0 +1,92 @@
+package com.baeldung.hexagonal.architecture;
+
+import com.baeldung.pattern.hexagonal.architecture.application.domain.Car;
+import com.baeldung.pattern.hexagonal.architecture.application.port.outgoing.LoadCarPort;
+import com.baeldung.pattern.hexagonal.architecture.application.port.outgoing.SaveCarPort;
+import com.baeldung.pattern.hexagonal.architecture.application.services.CarService;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.NoSuchElementException;
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.*;
+
+public class CarServiceUnitTest {
+
+    private LoadCarPort loadCarPort;
+    private SaveCarPort saveCarPort;
+
+    private CarService carService;
+
+
+    @BeforeEach
+    void setup() {
+        loadCarPort = mock(LoadCarPort.class);
+        saveCarPort = mock(SaveCarPort.class);
+
+        carService = new CarService(loadCarPort, saveCarPort);
+
+    }
+
+    @Test
+    void testRent_WhenCarNotFound_ThenShouldThrowNoSuchElementException() {
+        doReturn(Optional.empty()).when(loadCarPort).load(0L);
+        Assertions.assertThatExceptionOfType(NoSuchElementException.class).isThrownBy(() -> carService.rent(0L));
+    }
+
+    @Test
+    void testRent_WhenHasRentIsFalse_ThenShouldReturnFalse() {
+        Car car = mock(Car.class);
+
+        doReturn(false).when(car).rent();
+        doReturn(Optional.of(car)).when(loadCarPort).load(1L);
+
+        assertFalse(carService.rent(1L));
+        verify(saveCarPort, times(0)).save(car);
+    }
+
+    @Test
+    void testRent_WhenHasRentIsTrue_ThenShouldReturnTrue() {
+        Car car = mock(Car.class);
+
+        doReturn(true).when(car).rent();
+        doReturn(Optional.of(car)).when(loadCarPort).load(1L);
+
+        assertTrue(carService.rent(1L));
+        verify(saveCarPort, times(1)).save(car);
+    }
+
+    @Test
+    void testReturnRental_WhenCarNotFound_ThenShouldThrowNoSuchElementException() {
+        doReturn(Optional.empty()).when(loadCarPort).load(0L);
+        Assertions.assertThatExceptionOfType(NoSuchElementException.class).isThrownBy(() -> carService.returnRental(0L));
+    }
+
+    @Test
+    void testReturnRental_WhenHasReturnedIsFalse_ThenShouldReturnFalse() {
+        Car car = mock(Car.class);
+
+        doReturn(false).when(car).returnRental();
+        doReturn(Optional.of(car)).when(loadCarPort).load(1L);
+
+        assertFalse(carService.returnRental(1L));
+        verify(saveCarPort, times(0)).save(car);
+    }
+
+
+    @Test
+    void testReturnRental_WhenHasReturnedIsTrue_ThenShouldReturnTrue() {
+        Car car = mock(Car.class);
+
+        doReturn(true).when(car).returnRental();
+        doReturn(Optional.of(car)).when(loadCarPort).load(1L);
+
+        assertTrue(carService.returnRental(1L));
+        verify(saveCarPort, times(1)).save(car);
+    }
+
+}