kkaravitis@gmail.com hexagonal architecture in java

patterns/hexagonal-architecture-example/pom.xml

@@ -0,0 +1,34 @@
+<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>
+    <artifactId>hexagonal-architecture-example</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+	<parent>
+		<groupId>com.baeldung</groupId>
+		<artifactId>patterns</artifactId>
+		<version>1.0.0-SNAPSHOT</version>
+	</parent>
+	
+	<build>
+	  <plugins>
+	    <plugin>
+	      <!-- Build an executable JAR -->
+	      <groupId>org.apache.maven.plugins</groupId>
+	      <artifactId>maven-jar-plugin</artifactId>
+	      <version>3.2.0</version>
+	      <configuration>
+	        <archive>
+	          <manifest>
+	            <addClasspath>true</addClasspath>
+	            <classpathPrefix>lib/</classpathPrefix>
+	            <mainClass>com.baeldung.hexagonal.architecture.example.infrastructure.CocktailsMenuApp</mainClass>
+	          </manifest>
+	        </archive>
+	      </configuration>
+	    </plugin>
+	  </plugins>
+</build>
+	
+</project>

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/hexagonal/architecture/example/adapters/inbound/CommandLineAdapter.java

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+package com.baeldung.hexagonal.architecture.example.adapters.inbound;
+
+import java.util.List;
+import java.util.Scanner;
+
+import com.baeldung.hexagonal.architecture.example.application.domain.Cocktail;
+import com.baeldung.hexagonal.architecture.example.application.ports.in.AddCocktailPort;
+import com.baeldung.hexagonal.architecture.example.application.ports.in.AddCocktailPort.AddCocktailCommand;
+import com.baeldung.hexagonal.architecture.example.application.ports.in.GetCocktailsPort;
+
+public class CommandLineAdapter {
+    private AddCocktailPort addCocktailPort;
+    private GetCocktailsPort listCocktailsPort;
+    private Scanner scanner;
+
+    public CommandLineAdapter(Scanner scanner, AddCocktailPort addCocktailPort, GetCocktailsPort listCocktailsPort) {
+        this.addCocktailPort = addCocktailPort;
+        this.listCocktailsPort = listCocktailsPort;
+        this.scanner = scanner;
+    }
+
+    public void addCocktail() {
+        try {
+            System.out.println("Enter the name of the cocktail");
+            scanner.nextLine();
+            String name = scanner.nextLine();
+            System.out.println("Enter the price of the cocktail");
+            double price = scanner.nextDouble();
+            scanner.nextLine();
+            AddCocktailCommand command = new AddCocktailCommand(name, price);
+            addCocktailPort.addCocktail(command);
+        } catch (Exception exception) {
+            System.out.println("Error during adding a new Cocktail");
+        }
+    }
+
+    public void listCocktails() {
+        List<Cocktail> cocktailList = listCocktailsPort.getCocktails();
+        System.out.println("Cocktails menu: \n");
+        cocktailList.stream()
+            .forEach(cocktail -> {
+                System.out.println(cocktail.getName() + "\n" + 
+                    "price: " + cocktail.getPrice() + " $ " + "\n");
+            });
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/hexagonal/architecture/example/adapters/outbound/CocktailRepository.java

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+package com.baeldung.hexagonal.architecture.example.adapters.outbound;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.baeldung.hexagonal.architecture.example.application.domain.Cocktail;
+import com.baeldung.hexagonal.architecture.example.application.ports.out.FetchCocktailsPort;
+import com.baeldung.hexagonal.architecture.example.application.ports.out.SaveCocktailPort;
+
+public class CocktailRepository implements FetchCocktailsPort, SaveCocktailPort {
+    
+    private Map<String, Cocktail> store = new HashMap<>();
+
+    public List<Cocktail> fetchCocktails() {
+        return new ArrayList<>(store.values());
+    }
+
+    public void saveCocktail(Cocktail cocktail) {
+        store.put(cocktail.getName(), cocktail);
+    }
+}

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

@@ -0,0 +1,21 @@
+package com.baeldung.hexagonal.architecture.example.application.domain;
+
+public class Cocktail {
+    
+    private String name;
+    
+    private double price;
+
+    public Cocktail(String name, double price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/hexagonal/architecture/example/application/ports/in/AddCocktailPort.java

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+package com.baeldung.hexagonal.architecture.example.application.ports.in;
+
+public interface AddCocktailPort {
+
+    void addCocktail(AddCocktailCommand command);
+
+    class AddCocktailCommand {
+        private String name;
+        private double price;
+
+        public AddCocktailCommand(String name, double price) {
+            this.name = name;
+            this.price = price;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public double getPrice() {
+            return price;
+        }
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/hexagonal/architecture/example/application/ports/in/GetCocktailsPort.java

@@ -0,0 +1,9 @@
+package com.baeldung.hexagonal.architecture.example.application.ports.in;
+
+import java.util.List;
+
+import com.baeldung.hexagonal.architecture.example.application.domain.Cocktail;
+
+public interface GetCocktailsPort {
+    List<Cocktail> getCocktails();
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/hexagonal/architecture/example/application/service/AddCocktailService.java

@@ -0,0 +1,19 @@
+package com.baeldung.hexagonal.architecture.example.application.service;
+
+import com.baeldung.hexagonal.architecture.example.application.domain.Cocktail;
+import com.baeldung.hexagonal.architecture.example.application.ports.in.AddCocktailPort;
+import com.baeldung.hexagonal.architecture.example.application.ports.out.SaveCocktailPort;
+
+public class AddCocktailService implements AddCocktailPort {
+    private SaveCocktailPort saveCocktailPort;
+
+    public AddCocktailService(SaveCocktailPort saveCocktailPort) {
+        this.saveCocktailPort = saveCocktailPort;
+    }
+
+    @Override
+    public void addCocktail(AddCocktailCommand command) {
+        Cocktail cocktail = new Cocktail(command.getName(), command.getPrice());
+        saveCocktailPort.saveCocktail(cocktail);
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/hexagonal/architecture/example/application/service/GetCocktailsService.java

@@ -0,0 +1,20 @@
+package com.baeldung.hexagonal.architecture.example.application.service;
+
+import java.util.List;
+
+import com.baeldung.hexagonal.architecture.example.application.domain.Cocktail;
+import com.baeldung.hexagonal.architecture.example.application.ports.in.GetCocktailsPort;
+import com.baeldung.hexagonal.architecture.example.application.ports.out.FetchCocktailsPort;
+
+public class GetCocktailsService implements GetCocktailsPort {
+    private FetchCocktailsPort fetchCocktailsPort;
+
+    public GetCocktailsService(FetchCocktailsPort fetchCocktailsPort) {
+        this.fetchCocktailsPort = fetchCocktailsPort;
+    }
+
+    @Override
+    public List<Cocktail> getCocktails() {
+        return fetchCocktailsPort.fetchCocktails();
+    }
+}

patterns/hexagonal-architecture-example/src/main/java/com/baeldung/hexagonal/architecture/example/infrastructure/CocktailsMenuApp.java

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+package com.baeldung.hexagonal.architecture.example.infrastructure;
+
+import java.util.Scanner;
+
+import com.baeldung.hexagonal.architecture.example.adapters.inbound.CommandLineAdapter;
+import com.baeldung.hexagonal.architecture.example.adapters.outbound.CocktailRepository;
+import com.baeldung.hexagonal.architecture.example.application.service.AddCocktailService;
+import com.baeldung.hexagonal.architecture.example.application.service.GetCocktailsService;
+
+public class CocktailsMenuApp {
+    private static final String ADD = "add";
+    private static final String LIST = "list";
+    private static final String EXIT = "exit";
+    private static final String HELP_TEXT = "Enter command \n" + 
+        ADD + " - add a new Cocktail to the menu \n" + 
+        LIST + " - list cocktails \n" + 
+        EXIT + " - exit \n";
+    private static Scanner SCANNER = new Scanner(System.in);
+
+    public static void main(String[] args) {
+        CocktailRepository cocktailRepository = new CocktailRepository();
+        AddCocktailService addCocktailService = new AddCocktailService(cocktailRepository);
+        GetCocktailsService getCocktailsMenuService = new GetCocktailsService(cocktailRepository);
+        CommandLineAdapter commandLineAdapter = new CommandLineAdapter(SCANNER, addCocktailService, getCocktailsMenuService);
+        runWith(commandLineAdapter);
+    }
+
+    public static void runWith(CommandLineAdapter adapter) {
+        String command = null;
+        while (!EXIT.equalsIgnoreCase(command)) {
+            System.out.println(HELP_TEXT);
+            command = SCANNER.next();
+            switch (command.toLowerCase()) {
+            case ADD:
+                adapter.addCocktail();
+                break;
+            case LIST:
+                adapter.listCocktails();
+                break;
+            }
+        }
+    }
+}

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

@@ -0,0 +1,42 @@
+package com.baeldung.hexagonal.architecture.example.application;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mockito;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import com.baeldung.hexagonal.architecture.example.application.domain.Cocktail;
+import com.baeldung.hexagonal.architecture.example.application.ports.in.AddCocktailPort.AddCocktailCommand;
+import com.baeldung.hexagonal.architecture.example.application.ports.out.SaveCocktailPort;
+import com.baeldung.hexagonal.architecture.example.application.service.AddCocktailService;
+
+class AddCocktailUnitTest {
+    
+    SaveCocktailPort saveCocktailPort;
+    AddCocktailService addCocktailService;
+    
+    @BeforeEach
+    void setup() {
+        saveCocktailPort = mock(SaveCocktailPort.class);
+        addCocktailService = new AddCocktailService(saveCocktailPort); 
+    }
+    
+    @Test
+    void whenAddingACocktail_thenTheCocktailIsSaved() {
+        AddCocktailCommand command = mock(AddCocktailCommand.class);
+        when(command.getName()).thenReturn("mockito");
+        when(command.getPrice()).thenReturn(9.50);
+        ArgumentCaptor<Cocktail> captor = ArgumentCaptor.forClass(Cocktail.class);
+        
+        addCocktailService.addCocktail(command);
+        
+        Mockito.verify(saveCocktailPort).saveCocktail(captor.capture());
+        Cocktail cocktailThatSaved = captor.getValue();
+        assertEquals(command.getName(), cocktailThatSaved.getName());
+        assertEquals(command.getPrice(), cocktailThatSaved.getPrice());
+    }
+
+}

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

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+package com.baeldung.hexagonal.architecture.example.application;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.hexagonal.architecture.example.application.domain.Cocktail;
+import com.baeldung.hexagonal.architecture.example.application.ports.out.FetchCocktailsPort;
+import com.baeldung.hexagonal.architecture.example.application.service.GetCocktailsService;
+
+class GetCocktailsUnitTest {
+
+    FetchCocktailsPort fetchCocktailsPort;
+    GetCocktailsService getCocktailsService;
+
+    @BeforeEach
+    void setup() {
+        fetchCocktailsPort = mock(FetchCocktailsPort.class);
+        getCocktailsService = new GetCocktailsService(fetchCocktailsPort);
+    }
+
+    @Test
+    void whenGettingCocktails_thenCocktailsFetchedFromPortAndReturned() {
+        Cocktail cocktail = mock(Cocktail.class);
+        when(cocktail.getName()).thenReturn("zombie");
+        when(cocktail.getPrice()).thenReturn(12.00);
+        when(fetchCocktailsPort.fetchCocktails()).thenReturn(List.of(cocktail));
+
+        List<Cocktail> cocktails = getCocktailsService.getCocktails();
+        
+        assertEquals(1, cocktails.size());
+        assertEquals(cocktail.getName(), cocktails.get(0).getName());
+        assertEquals(cocktail.getPrice(), cocktails.get(0).getPrice());
+    }
+
+}

patterns/pom.xml

@@ -24,6 +24,7 @@
         <module>front-controller</module>
         <module>intercepting-filter</module>
         <module>solid</module>
+        <module>hexagonal-architecture-example</module>
     </modules>
 
     <dependencyManagement>