MapStruct : mapping multiple source fields to one target field

Question

Consider the following POJOs:

public class PersonVo {
    private String firstName;
    private String lastName;
}

private class PersonEntity {
    private String fullName;
}

Using MapStruct, I want create mapper that PersonVo to PersonEntity.
I need mapping multiple source fields firstName, lastName to one target filed fullName.

Here is pseudo code what I want to.

[Want Solution A]

@Mapper
public interface PersonMapper {
    @Mapping(target = "fullName", source = {"firstName", "lastName"}, qualifiedByName="toFullName")
    PersonEntity toEntity(PersonVo person);

    @Named("toFullName")
    String translateToFullName(String firstName, String lastName) {
        return firstName + lastName;
    }
}

[Want Solution B]

@Mapper
public interface PersonMapper {
    @Mapping(target = "fullName", source = PersonVo.class, qualifiedByName="toFullName")
    PersonEntity toEntity(PersonVo person);

    @Named("toFullName")
    String translateToFullName(PersonVo pserson) {
        return pserson.getFirstName() + pserson.getLastName();
    }
}

Is there any way this can be achieved?

Answer 1

Here is my answer.

@Mapper
public interface PersonMapper {
    @Mapping(target = "fullName", source = ".", qualifiedByName="toFullName")
    PersonEntity toEntity(PersonVo person);

    @Named("toFullName")
    String translateToFullName(PersonVo pserson) {
        return pserson.getFirstName() + pserson.getLastName();
    }
}

Main point is that

@Mapping(target = "fullName", source = ".", qualifiedByName="toFullName")

It can make use source object by parameter.

Answer 2

First I would go with public abstract class for Mappers. Makes it easier to extend them and create inheritance between the generated code and the abstract class. But here is your solution: You can achieve this by creating a @AfterMapping annotated method. So something like

@AfterMapping
default void concat(@MappingTarget PersonEntity person, PersonVo person) {
  ... manipulate the target value
}

MapStruct documentation