How can I change a value of an id attribute to its equivalent description in DTO class using mapstruct

Question

I have a 1 entity class PersonEntity and corresponding to that I have Dto class

@Entity(value="person")

class PersonEntity{

String name;

String id;

}

**DTO** 

class PersonDto{
String name;

String id;

String desc; (This is a lookup from a map with id attribute)
}

In my mapper class, I am able to change my entity list to Dto list with below code.

public interface MyMapper{

List<PersonDto> entityListToDtoList(<List<PersonEntity>)

}

How can I use my lookup map to get the description and set in my DTO class. I am not able to figure out how to determine the value with below code.

List<PersonDto> entityListToDtoList(<List<PersonEntity>,@Context Map<String,String> lookupMap)

Answer 1

You have to define the PersonEntity to PersonDto method and add a @Mapping with an expression for that. See the following example:

    @Mapping( target = "desc", expression = "java(lookupMap.get(person.getId()))" )
    PersonDto entityToDto(PersonEntity person, @Context Map<String, String> lookupMap);

    List<PersonDto> entityListToDtoList(List<PersonEntity> persons, @Context Map<String, String> lookupMap);