Jakarta Validation - Lab 1

In this lab we will create a model class with the Jakarta Validation annotations.

1. Create the validation class

Steps

1. Open the 01-jakarta-ee project and navigate to the src/main/java
2. Create a class called Worker in the expert.os.labs.persistence.validation package

3. Add the following fields, adding the related annotations from the jakarta.validation.constraints package

   • nickname field with @NotBlank annotation

     @NotBlank(message = "Nickname cannot be blank")
     private String nickname;
     

   • name field with @NotBlank annotation

     @NotBlank(message = "Name cannot be blank")
     private String name;
     

   • working field with @AssertTrue annotation

     @AssertTrue
     private boolean working;
     

   • bio field with @Size annotation:

     @Size(min = 10, max = 200, message = "Bio must be between 10 and 200 characters")
     private String bio;
     

   • age field with @Min and @Max annotations

     @Min(value = 18, message = "A worker should not be less than 18")
     @Max(value = 80, message = "A worker should not be greater than 80")
     private int age;
     

   • email field with @Email annotation:

     @Email(message = "Email should be valid")
     private String email;
     

Expected results

• Class called Worker created in the src/main/java at the expert.os.labs.persistence.validation with all the Jakarta Validation annotations

Solution

Click to see...

import jakarta.validation.constraints.AssertTrue;
import jakarta.validation.constraints.Email;
import jakarta.validation.constraints.Max;
import jakarta.validation.constraints.Min;
import jakarta.validation.constraints.NotBlank;
import jakarta.validation.constraints.Size;

public class Worker {
   @NotBlank(message = "Nickname cannot be blank")
   private String nickname;

   @NotBlank(message = "Name cannot be blank")
   private String name;

   @AssertTrue
   private boolean working;

   @Size(min = 10, max = 200, message = "Bio must be between 10 and 200 characters")
   private String bio;

   @Min(value = 18, message = "A worker should not be less than 18")
   @Max(value = 80, message = "A worker should not be greater than 80")
   private int age;

   @Email(message = "Email should be valid")
   private String email;
}

2. Add the constructor, getters, setters, and toString

Steps

Tips

You can use the shortcuts in your preffered IDE to generate the constructor, getters, setterns and toString()

• IntelliJ IDEA: press Command + N and click in the related item
• Visual Studio Code: right-click in the code, click in the Source Action and then in the related item

1. Add a constructor with all the fields present in the class
2. Add the getters and setters for all the fields present in the class
3. Add the toString() method with all the fields present in the class
   • don't forget to add the @Override

Expected results

• The Worker class with the:
  • constructor
  • getters and setters
  • toString()

Solution

Click to see...

    public class Worker {
       @NotBlank(message = "Nickname cannot be blank")
       private String nickname;

       @NotBlank(message = "Name cannot be blank")
       private String name;

       @AssertTrue
       private boolean working;

       @Size(min = 10, max = 200, message = "Bio must be between 10 and 200 characters")
       private String bio;

       @Min(value = 18, message = "A worker should not be less than 18")
       @Max(value = 80, message = "A worker should not be greater than 80")
       private int age;

       @Email(message = "Email should be valid")
       private String email;

       public Worker(String nickname, String name, boolean working, String bio, int age, String email) {
          this.nickname = nickname;
          this.name = name;
          this.working = working;
          this.bio = bio;
          this.age = age;
          this.email = email;
       }

       public String getNickname() {
          return nickname;
       }

       public void setNickname(String nickname) {
          this.nickname = nickname;
       }

       public String getName() {
          return name;
       }

       public void setName(String name) {
          this.name = name;
       }

       public boolean isWorking() {
          return working;
       }

       public void setWorking(boolean working) {
          this.working = working;
       }

       public String getBio() {
          return bio;
       }

       public void setBio(String bio) {
          this.bio = bio;
       }

       public int getAge() {
          return age;
       }

       public void setAge(int age) {
          this.age = age;
       }

       public String getEmail() {
          return email;
       }

       public void setEmail(String email) {
          this.email = email;
       }

       @Override
       public String toString() {
          return "Worker{" +
          "nickname='" + nickname + '\'' +
          ", name='" + name + '\'' +
          ", working=" + working +
          ", bio='" + bio + '\'' +
          ", age=" + age +
          ", email='" + email + '\'' +
          '}';
       }
    }

3. Create a builder for the Worker class

Steps

1. Create a class called WorkerBuilder in the src/main/java folder at the expert.os.labs.persistence.validation package
2. Add the same fields we had previously added to the Worker class, without the annotations

   private String nickname;
   private String name;
   private boolean working;
   private String bio;
   private int age;
   private String email;
   

3. Add the builder methods for each field

   • example using the nickname field

     public WorkerBuilder nickname(String nickname) {
        this.nickname = nickname;
        return this;
     }
     

4. Add the build() method creating a new instance of Worker using its constructor

5. In the Worker class add the builder method referring to the WorkerBuilder

   public static WorkerBuilder build() {
      return new WorkerBuilder();
   }
   

Expected results

• A new WorkerBuilder class implementing the Builder pattern for the Worker class
• A new builder() method in the Worker class

Solution

Click to see...

public class WorkerBuilder {
   private String nickname;
   private String name;
   private boolean working;
   private String bio;
   private int age;
   private String email;

   public WorkerBuilder nickname(String nickname) {
      this.nickname = nickname;
      return this;
   }

   public WorkerBuilder name(String name) {
      this.name = name;
      return this;
   }

   public WorkerBuilder working(boolean working) {
      this.working = working;
      return this;
   }

   public WorkerBuilder bio(String bio) {
      this.bio = bio;
      return this;
   }

   public WorkerBuilder age(int age) {
      this.age = age;
      return this;
   }

   public WorkerBuilder email(String email) {
      this.email = email;
      return this;
   }

   public Worker build() {
      return new Worker(nickname, name, working, bio, age, email);
   }
}

3. Test the validations

Steps

1. Create a class called WorkerTest in the src/test/java folder at the expert.os.labs.persistence.validation package

2. Add a field called validator using the Validator class from the jakarta.validation.Validator package

   private Validator validator;
   

3. Create a setup that will create a validator

   @BeforeEach
   public void setUp() {
      ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
      validator = factory.getValidator();
   }
   

4. Create, at least, one of the following possible tests based on the validations we have added into the Worker class

   field	test
   nickname	blank nickname
   name	blank name
   working	work set as false
   bio	bio less than 10 or greater than 200
   age	age less than 18 or greater than 80
   email	invalid e-mail

   • use the following code template as a test

     @Test
     void shouldNotCreateWorkerWithBlankNickname() {
        Worker worker = Worker.builder().nickname("").name("John Doe").working(true)
            .bio("I am a software engineer").age(38).email("john.doe@gmail.com").build();
        Set<ConstraintViolation<Worker>> violations = validator.validate(worker);
     
        Assertions.assertThat(violations).isNotEmpty().hasSize(1)
           .map(ConstraintViolation::getMessage).contains("Nickname cannot be blank");
        }
     

   • note that the Assertions class comes from the org.assertj.core.api.Assertions.assertThat and must be statically imported

5. Run the test

Expected results

• A new WorkerTest class created
• At least one test implemented
• Tests running without problems

Solution

Click to see...

class WorkerTest {

   private Validator validator;

   @BeforeEach
   public void setUp() {
      ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
      validator = factory.getValidator();
   }

   @Test
   void shouldNotCreateWorkerWithBlankNickname1() {
      Worker worker = Worker.builder().nickname("").name("John").working(true).bio("Bio of Elias").age(38).email("elias@elias.com").build();
      Set<ConstraintViolation<Worker>> violations = validator.validate(worker);

         assertThat(violations)
         .isNotEmpty()
         .hasSize(1)
         .map(ConstraintViolation::getMessage).contains("Nickname cannot be blank");
      }
   }