MapStruct set field value to a result of another mapper method

Question

Given classes

public static class Source {
    private int a;
    private int b;
}

public static class DataHolder {
    private int c;
}

public static class Target {
    private int a;
    private int b;
    private DataHolder holder;
}

and mapper

@Mapper
public interface SourceToDataHolderMapper {

    DataHolder sourceToDataHolder(Source src);

}

I want to implement another mapper that maps Source to Target utilizing SourceToDataHolderMapper mapper for holder field in Target type:

@Mapper
public interface SourceToTargetMapper {

    @Mapping(target = "holder", ???)
    Target sourceToTarget(Source src);

}

I don't know what to use in place of ??? so that Mapstruct would use my SourceToDataHolderMapper correctly.

I tried setting import and uses for type SourceToDataHolderMapper in @Mapper annotation, but it wasn't working.

Answer 1

After a few dirty attempts of using expression="java(...)" for @Mapping annotation I found a solution:

@Mapper(uses = SourceToDataHolderMapper.class)
public interface SourceToTargetMapper {

    @Mapping(target = "holder", source = ".")
    Target sourceToTarget(Source src);

}

Which generates implementation code like this:

public static class SourceToTargetMapperImpl {
    private SourceToDataHolderMapper sourceToDataHolderMapper = Mappers.getMapper(SourceToDataHolderMapper.class);

    public Target sourceToTarget(Source src) {
        if ( src == null ) return null;
        Target target = new Target();
        target.setA( src.getA() );
        target.setB( src.getB() );
        target.setHolder( sourceToDataHolderMapper.sourceToDataHolder( src ) );
    }

}

That is exactly what I wanted without using expression