Lombok's builder with mandatory parameters

Question

If I add @Builder to a class. The builder method is created.

Person.builder().name("john").surname("Smith").build();

I have a requirement where a particular field is mandatory. In this case, the name field is mandatory. Ideally, I would like to declare it like so.

Person.builder("john").surname("Smith").build();

When googling i found many alternatives like overriding the builder implementation as below:

@Builder
public class Person {

    private String name;
    private String surname;

    public static PersonBuilder builder(String name) {
        return new PersonBuilder().name(name);
    }
}

And then use it like below:

Person p = Person.builder("Name").surname("Surname").build();

The problem with above approach is that it still provides the name() and PersonBuilder() method like below, which i don't want:

Person p = Person.builder("Name").surname("Surname").name("").build();

Person p = new Person.PersonBuilder().build;

Another approach is to add @lombok.nonnull check at name which will force to provide value for name while creating object. but it is a runtime check. it will not force me to provide value for name while creating object.

Is there any additional technique which lombok provides to achieve below:

 Person p = Person.builder("Name").surname("Surname").build();

Note: The builder() and name() should not be exposed. The only way to create Person object should be either above or below:

 Person p = Person.builder("Name").build();

Answer 1

You can't really do it with lombok, see the explanation from the library authors. But is it that complicated to roll this builder on your own?

public static class PersonBuilder {

    private final String name;
    private String surname;

    PersonBuilder(String name) {
        this.name = name;
    }

    public PersonBuilder surname(String surname) {
        this.surname = surname;
        return this;
    }

    public Person build() {
        return new Person(name, surname);
    }
        
}

with the same method that you already have:

    public static PersonBuilder builder(String name) {
        return new PersonBuilder(name);
    }

Answer 2

Try to make the builder private.

Did you check this comment Required arguments with a Lombok @Builder

I am pretty sure you will find out once read the thread one more time.

P.S. If you have a class with only two field better use directly a constructor.