small example of hexagonal architecture in java

ddd-modules/hexagonalarchitecture/README.md

@@ -0,0 +1,3 @@
+This module contains articles about hexagonal architecture in java
+
+### Relevant articles

ddd-modules/hexagonalarchitecture/pom.xml

@@ -0,0 +1,35 @@
+<?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">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <artifactId>ddd-modules</artifactId>
+    <groupId>com.baeldung.dddmodules</groupId>
+    <version>1.0</version>
+  </parent>
+
+  <groupId>com.baeldung.dddmodules.hexagonalarchitecture</groupId>
+  <artifactId>hexagonalarchitecture</artifactId>
+  <version>1.0</version>
+  <packaging>jar</packaging>
+
+  <name>hexagonalarchitecture</name>
+
+    <build>
+      <plugins>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <configuration>
+            <source>${maven.compiler.source}</source>
+            <target>${maven.compiler.target}</target>
+          </configuration>
+        </plugin>
+      </plugins>
+    </build>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+  </properties>
+</project>

ddd-modules/hexagonalarchitecture/src/main/java/com/baeldung/dddmodules/hexagonalarchitecture/adapters/InMemoryUserPersistenceImpl.java

@@ -0,0 +1,14 @@
+package com.baeldung.dddmodules.hexagonalarchitecture.adapters;
+
+import com.baeldung.dddmodules.hexagonalarchitecture.ports.UserPersistence;
+import com.baeldung.dddmodules.hexagonalarchitecture.core.User;
+
+import java.util.UUID;
+
+class InMemoryUserPersistenceImpl implements UserPersistence {
+    @Override
+    public User createUser(User user) {
+        user.setId(UUID.randomUUID());
+        return user;
+    }
+}

ddd-modules/hexagonalarchitecture/src/main/java/com/baeldung/dddmodules/hexagonalarchitecture/adapters/Main.java

@@ -0,0 +1,13 @@
+package com.baeldung.dddmodules.hexagonalarchitecture.adapters;
+
+import com.baeldung.dddmodules.hexagonalarchitecture.core.User;
+import com.baeldung.dddmodules.hexagonalarchitecture.core.UserServiceImpl;
+import com.baeldung.dddmodules.hexagonalarchitecture.ports.UserService;
+
+public class Main {
+
+    public static void main(String[] args) {
+        UserService userService = new UserServiceImpl(new InMemoryUserPersistenceImpl());
+        User user = userService.createUser(new User("John", "Doe"));
+    }
+}

ddd-modules/hexagonalarchitecture/src/main/java/com/baeldung/dddmodules/hexagonalarchitecture/core/User.java

@@ -0,0 +1,43 @@
+package com.baeldung.dddmodules.hexagonalarchitecture.core;
+
+import java.util.UUID;
+
+public class User {
+    private UUID id;
+    private String firstName;
+    private String lastName;
+
+    public User(String firstName, String lastName) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public UUID getId() {
+        return id;
+    }
+
+    public void setId(UUID id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    @Override
+    public String toString() {
+        return "User{" + "id=" + id + ", firstName='" + firstName + '\'' + ", lastName='" + lastName + '\'' + '}';
+    }
+}

ddd-modules/hexagonalarchitecture/src/main/java/com/baeldung/dddmodules/hexagonalarchitecture/core/UserServiceImpl.java

@@ -0,0 +1,17 @@
+package com.baeldung.dddmodules.hexagonalarchitecture.core;
+
+import com.baeldung.dddmodules.hexagonalarchitecture.ports.UserPersistence;
+import com.baeldung.dddmodules.hexagonalarchitecture.ports.UserService;
+
+public class UserServiceImpl implements UserService {
+    private UserPersistence userPersistence;
+
+    public UserServiceImpl(UserPersistence userPersistence) {
+        this.userPersistence = userPersistence;
+    }
+
+    @Override
+    public User createUser(User userToCreate) {
+        return userPersistence.createUser(userToCreate);
+    }
+}

ddd-modules/hexagonalarchitecture/src/main/java/com/baeldung/dddmodules/hexagonalarchitecture/ports/UserPersistence.java

@@ -0,0 +1,7 @@
+package com.baeldung.dddmodules.hexagonalarchitecture.ports;
+
+import com.baeldung.dddmodules.hexagonalarchitecture.core.User;
+
+public interface UserPersistence {
+    User createUser(User user);
+}

ddd-modules/hexagonalarchitecture/src/main/java/com/baeldung/dddmodules/hexagonalarchitecture/ports/UserService.java

@@ -0,0 +1,7 @@
+package com.baeldung.dddmodules.hexagonalarchitecture.ports;
+
+import com.baeldung.dddmodules.hexagonalarchitecture.core.User;
+
+public interface UserService {
+    User createUser(User userToCreate);
+}

ddd-modules/pom.xml

@@ -1,8 +1,5 @@
-<?xml version="1.0" encoding="UTF-8"?>
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<project
+<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">
-    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.dddmodules</groupId>
     <artifactId>ddd-modules</artifactId>
@@ -23,7 +20,8 @@
         <module>shippingcontext</module>
         <module>ordercontext</module>
         <module>mainapp</module>
-    </modules>
+      <module>hexagonalarchitecure</module>
+  </modules>
 
     <dependencyManagement>
         <dependencies>