Use Value Objects for Student

Author: OctaviPascual

apps/test/tv/codely/apps/mooc/backend/controller/students/StudentsPutControllerShould.java

@@ -9,7 +9,7 @@ void register_a_valid_non_existing_student() throws Exception {
         assertRequestWithBody(
             "PUT",
             "/students/1bab45ba-3c7a-4344-8936-78466eca17fa",
-            "{\"name\": \"some-name\", \"surname\": \"some-surname\", \"email\": \"some-email\"}",
+            "{\"name\": \"some-name\", \"surname\": \"some-surname\", \"email\": \"email@email.com\"}",
             201
         );
     }

src/mooc/main/tv/codely/mooc/students/application/StudentResponse.java

@@ -17,7 +17,12 @@ public StudentResponse(String id, String name, String surname, String email) {
     }
 
     public static StudentResponse fromAggregate(Student student) {
-        return new StudentResponse(student.id().value(), student.name(), student.surname(), student.email());
+        return new StudentResponse(
+            student.id().value(),
+            student.name().value(),
+            student.surname().value(),
+            student.email().value()
+        );
     }
 
     public String id() {

src/mooc/main/tv/codely/mooc/students/application/register/StudentRegistrar.java

@@ -1,8 +1,6 @@
 package tv.codely.mooc.students.application.register;
 
-import tv.codely.mooc.students.domain.Student;
-import tv.codely.mooc.students.domain.StudentId;
-import tv.codely.mooc.students.domain.StudentRepository;
+import tv.codely.mooc.students.domain.*;
 import tv.codely.shared.domain.Service;
 
 @Service
@@ -14,7 +12,12 @@ public StudentRegistrar(StudentRepository repository) {
     }
 
     public void register(RegisterStudentRequest request) {
-        Student student = Student.create(new StudentId(request.id()), request.name(), request.surname(), request.email());
+        Student student = Student.create(
+            new StudentId(request.id()),
+            new StudentName(request.name()),
+            new StudentSurname(request.surname()),
+            new StudentEmail(request.email())
+        );
         repository.register(student);
     }
 }

src/mooc/main/tv/codely/mooc/students/domain/Student.java

@@ -3,35 +3,35 @@
 import java.util.Objects;
 
 public final class Student {
-    private final StudentId id;
-    private final String    name;
-    private final String    surname;
-    private final String    email;
+    private final StudentId      id;
+    private final StudentName    name;
+    private final StudentSurname surname;
+    private final StudentEmail   email;
 
-    public Student(StudentId id, String name, String surname, String email) {
+    public Student(StudentId id, StudentName name, StudentSurname surname, StudentEmail email) {
         this.id      = id;
         this.name    = name;
         this.surname = surname;
         this.email   = email;
     }
 
-    public static Student create(StudentId id, String name, String surname, String email) {
+    public static Student create(StudentId id, StudentName name, StudentSurname surname, StudentEmail email) {
         return new Student(id, name, surname, email);
     }
 
     public StudentId id() {
         return id;
     }
 
-    public String name() {
+    public StudentName name() {
         return name;
     }
 
-    public String surname() {
+    public StudentSurname surname() {
         return surname;
     }
 
-    public String email() {
+    public StudentEmail email() {
         return email;
     }
 

src/mooc/main/tv/codely/mooc/students/domain/StudentEmail.java

@@ -0,0 +1,9 @@
+package tv.codely.mooc.students.domain;
+
+import tv.codely.shared.domain.EmailValueObject;
+
+public final class StudentEmail extends EmailValueObject {
+    public StudentEmail(String email) {
+        super(email);
+    }
+}

src/mooc/main/tv/codely/mooc/students/domain/StudentName.java

@@ -0,0 +1,9 @@
+package tv.codely.mooc.students.domain;
+
+import tv.codely.shared.domain.StringValueObject;
+
+public final class StudentName extends StringValueObject {
+    public StudentName(String value) {
+        super(value);
+    }
+}

src/mooc/main/tv/codely/mooc/students/domain/StudentSurname.java

@@ -0,0 +1,9 @@
+package tv.codely.mooc.students.domain;
+
+import tv.codely.shared.domain.StringValueObject;
+
+public final class StudentSurname extends StringValueObject {
+    public StudentSurname(String value) {
+        super(value);
+    }
+}

src/mooc/main/tv/codely/mooc/students/infrastructure/InMemoryStudentRepository.java

@@ -1,8 +1,6 @@
 package tv.codely.mooc.students.infrastructure;
 
-import tv.codely.mooc.students.domain.Student;
-import tv.codely.mooc.students.domain.StudentId;
-import tv.codely.mooc.students.domain.StudentRepository;
+import tv.codely.mooc.students.domain.*;
 import tv.codely.shared.domain.Service;
 import tv.codely.shared.domain.UuidGenerator;
 
@@ -20,11 +18,22 @@ public InMemoryStudentRepository(UuidGenerator generator) {
     @Override
     public List<Student> searchAll() {
         return Arrays.asList(
-            new Student(new StudentId(generator.generate()), "name", "surname", "email@mail.com"),
-            new Student(new StudentId(generator.generate()), "Other name", "Other surname", "another@mail.com")
+            new Student(
+                new StudentId(generator.generate()),
+                new StudentName("name"),
+                new StudentSurname("surname"),
+                new StudentEmail("email@mail.com")
+            ),
+            new Student(
+                new StudentId(generator.generate()),
+                new StudentName("Other name"),
+                new StudentSurname("Other surname"),
+                new StudentEmail("another@mail.com")
+            )
         );
     }
 
     @Override
-    public void register(Student student) {}
+    public void register(Student student) {
+    }
 }

src/mooc/test/tv/codely/mooc/students/application/register/StudentRegistrarTestShould.java

@@ -1,9 +1,7 @@
 package tv.codely.mooc.students.application.register;
 
 import org.junit.jupiter.api.Test;
-import tv.codely.mooc.students.domain.Student;
-import tv.codely.mooc.students.domain.StudentId;
-import tv.codely.mooc.students.domain.StudentRepository;
+import tv.codely.mooc.students.domain.*;
 import tv.codely.shared.domain.UuidMother;
 
 import static org.mockito.Mockito.*;
@@ -14,12 +12,14 @@ void register_a_valid_student() {
         StudentRepository repository = mock(StudentRepository.class);
         StudentRegistrar  registrar  = new StudentRegistrar(repository);
 
-        StudentId id      = new StudentId(UuidMother.random());
-        String    name    = "name";
-        String    surname = "surname";
-        String    email   = "email";
+        StudentId      id      = new StudentId(UuidMother.random());
+        StudentName    name    = new StudentName("name");
+        StudentSurname surname = new StudentSurname("surname");
+        StudentEmail   email   = new StudentEmail("email@email.com");
 
-        RegisterStudentRequest request = new RegisterStudentRequest(id.value(), name, surname, email);
+        RegisterStudentRequest request = new RegisterStudentRequest(
+            id.value(), name.value(), surname.value(), email.value()
+        );
 
         Student student = new Student(id, name, surname, email);
 

src/shared/main/tv/codely/shared/domain/EmailValueObject.java

@@ -0,0 +1,47 @@
+package tv.codely.shared.domain;
+
+import org.hibernate.validator.internal.constraintvalidators.hv.EmailValidator;
+
+import java.util.Objects;
+
+public abstract class EmailValueObject {
+    private static final EmailValidator emailValidator = new EmailValidator();
+    private final        String         email;
+
+    public EmailValueObject(String email) {
+        ensureValidEmail(email);
+        this.email = email;
+    }
+
+    public String value() {
+        return email;
+    }
+
+    private void ensureValidEmail(String value) {
+        if (!emailValidator.isValid(value, null)) {
+            throw new InvalidEmail(value);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return this.value();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (!(o instanceof EmailValueObject)) {
+            return false;
+        }
+        EmailValueObject that = (EmailValueObject) o;
+        return Objects.equals(email, that.email);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(email);
+    }
+}