How to map DTOs with missing fields to hierarcical domain entites using Mapstruct?

Question

I have a domain base class like this:

@Data
@SuperBuilder
@NoArgsConstructor
@AllArgsConstructor
public class Product {

    private UUID id;
    private Category category;

}

The Category field is enum:

public enum Category {

    BOOK("book"),
    PHONE("phone");

    private String name;

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

    public static Category fromName(String name) {
        for (Category category : values()) {
            if (category.getName().equals(name)) {
                return category;
            }
        }
        return null;
    }

    public String getName() {
        return this.name;
    }

}

There is a class that extends product:

@Data
@EqualsAndHashCode(callSuper = true)
@SuperBuilder
@NoArgsConstructor
@AllArgsConstructor
public class Book extends Product {

    private String title;
    private String isbn;
    private Author author;

}

And the DTO class:

@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class BookDtoRest {

    private String title;
    private String isbn;
    private Author author;

}

I want to map the BookDtoRest to Book upon receiving the request. I want the newly created book to have the parent's fields id and category populated appropriately. You can forget about the Author for the moment.

How can I do that with Mapstruct?

Answer 1

I would have a quick look at: bealdung

@Mapper
public interface BookMapper{
    Book sourceToDestination(BookDtoRest source);
}

Building your project through maven / gradle, should create a BookMapperImpl class, which contains a mapping method. With the above Mapstruct will create the mapper class, as the fields are the same no custome mapping needs to be defined.

hope it helps