Hexagonal Architecture: Robust Software With Interfaces Instead of Layers

Slide 1

Slide 1 text

Slide 2

Slide 2 text

Slide 3

Slide 3 text

Copyright © 2025, HappyCoders.eu “The goal of a software architecture is to minimize the human resources required to build and maintain the required system.” “If that eﬀort is low, and stays low throughout the lifetime of the system, the design is good.” What Is the Goal of Software Architecture?

Slide 4

Slide 4 text

Copyright © 2025, HappyCoders.eu A good architecture makes it possible to change software during its lifetime with as little eﬀort as possible. “To keep software soft.” — Robert C. Martin What Is the Goal of Software Architecture?

Slide 5

Slide 5 text

Slide 6

Slide 6 text

Slide 7

Slide 7 text

Slide 8

Slide 8 text

Copyright © 2025, HappyCoders.eu Goals 1. 2. 3. Isolation from controlling infrastructure Isolation from controlled infrastructure Modernization of infrastructure without adapting the business logic Business logic @

Slide 9

Slide 9 text

Slide 10

Slide 10 text

Slide 11

Slide 11 text

Slide 12

Slide 12 text

Slide 13

Slide 13 text

Slide 14

Slide 14 text

Slide 15

Slide 15 text

Copyright © 2025, HappyCoders.eu Registration Port Copyright © 2025, HappyCoders.eu name=Sven&email= [email protected] Submit Web UI Adapter registerPort.registerUser( "Sven", "[email protected]"); { "name": "Sven", "email": "… " } REST API Adapter Fill out

Slide 16

Slide 16 text

Copyright © 2025, HappyCoders.eu Copyright © 2024, HappyCoders.eu Persistence Port JPA Adapter INSERT INTO User (name, email, registrationDate) VALUES ('Sven', '[email protected]', now()); persistencePort .saveUser(user); Copyright © 2025, HappyCoders.eu

Slide 17

Slide 17 text

Slide 18

Slide 18 text

Copyright © 2025, HappyCoders.eu RegisterUserService +registerUser() UserRestController +registerUser() RESTEasy JpaAdapter +saveUser() Hibernate Copyright © 2025, HappyCoders.eu Module “Application” Module “Controllers” «interface» RegisterUserPort +registerUser() Direction of call

Slide 19

Slide 19 text

Slide 20

Slide 20 text

Copyright © 2025, HappyCoders.eu Copyright © 2025, HappyCoders.eu «interface» RegisterUserPort +registerUser() UserRestController +registerUser() RESTEasy Hibernate RegisterUserService +registerUser() JpaAdapter +saveUser() «interface» PersistencePort +saveUser() D irection of call D ependency

Slide 21

Slide 21 text

Slide 22

Slide 22 text

Slide 23

Slide 23 text

Slide 24

Slide 24 text

Slide 25

Slide 25 text

Copyright © 2025, HappyCoders.eu import jakarta.persistence.Column; import jakarta.persistence.Entity; import jakarta.persistence.Id; import java.time.LocalDateTime; @Entity public class User { @Id private Long id; @Column(nullable = false) private String name; @Column(nullable = false) private String email; @Column(nullable = false) private Instant registeredAt; // ... }

Slide 26

Slide 26 text

Slide 27

Slide 27 text

Slide 28

Slide 28 text

Slide 29

Slide 29 text

Slide 30

Slide 30 text

Slide 31

Slide 31 text

Slide 32

Slide 32 text

Copyright © 2025, HappyCoders.eu import jakarta.persistence.Column; import jakarta.persistence.Entity; import jakarta.persistence.Id; import java.time.Instant; @Entity public class JpaUser { @Id private Long id; @Column(nullable = false) private String name; @Column(nullable = false) private String email; @Column(nullable = false) private Instant registeredAt; // ... } import java.time.Instant; public class User { private Long id; private String name; private String email; private Instant registeredAt; public User(String name, String email) { verifyName(name); verifyEmail(email); this.name = name; this.email = email; this.registeredAt = Instant.now(); } // ... }

Slide 33

Slide 33 text

Slide 34

Slide 34 text

Slide 35

Slide 35 text

Copyright © 2025, HappyCoders.eu public class JpaAdapter implements PersistencePort { @Override @Transactional public void saveUser(User user) { JpaUser jpaUser = mapper.toJpaUser(user); repository.save(jpaUser); } } @Override @Transactional public Optional loadUser(long userId) { Optional jpaUser = repository.findById(userId); return jpaUser.map(mapper::toUser); }

Slide 36

Slide 36 text

Slide 37

Slide 37 text

Slide 38

Slide 38 text

Slide 39

Slide 39 text

Copyright © 2025, HappyCoders.eu import com.fasterxml.jackson.annotation.JsonFormat; import java.time.Instant; public class UserDto { private Long id; private String name; private String email; @JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss'Z'") private Instant registeredAt; // ... }

Slide 40

Slide 40 text

Copyright © 2025, HappyCoders.eu «interface» RegisterUserPort +registerUser() UserRestController + registerUser() RESTEasy RegisterUserService +registerUser() Copyright © 2025, HappyCoders.eu User UserDto Jackson Mapping

Slide 41

Slide 41 text

Slide 42

Slide 42 text

Slide 43

Slide 43 text

Slide 44

Slide 44 text

Slide 45

Slide 45 text

Slide 46

Slide 46 text

Slide 47

Slide 47 text

Slide 48

Slide 48 text

Slide 49

Slide 49 text

Slide 50

Slide 50 text

Slide 51

Slide 51 text

Slide 52

Slide 52 text

Slide 53

Slide 53 text

Slide 54

Slide 54 text

Slide 55

Slide 55 text

Slide 56

Slide 56 text

Slide 57

Slide 57 text

Slide 58

Slide 58 text

Slide 59

Slide 59 text

Slide 60

Slide 60 text

Slide 61

Slide 61 text

Slide 62

Slide 62 text

Slide 63

Slide 63 text

Slide 64

Slide 64 text

Slide 65

Slide 65 text

Slide 66

Slide 66 text

Slide 67

Slide 67 text

Slide 68

Slide 68 text

Slide 69

Slide 69 text

Slide 70

Slide 70 text

Slide 71

Slide 71 text

Slide 72

Slide 72 text

Slide 73

Slide 73 text

Slide 74

Slide 74 text

Slide 75

Slide 75 text

Copyright © 2025, HappyCoders.eu Links https://youtube.com/c/happycoders https://x.com/svenwoltmann https://www.happycoders.eu/ https://linkedin.com/in/sven-woltmann/ [email protected] https://bsky.app/proﬁle/sven.woltmann