Breaking a tree structure while mapping with ModelMapper

[Willix]

Hi

I've got a tree-like structure of entities that I'm trying to map to DTOs using ModelMapper. The trick is that I'm trying to break the graph after the first parent.

Following is a example of what I'm trying to do (I'm trying to get it to turn green :-) . I've got a Category entity which has a name and a parent Category. I want my DTO to have a link to it's parent but don't want the latter to have it's own parent (so that I don't get the whole hierarchy)

The trouble is that ModelMapper does not map my DTO's parent because it's of a different type; I declared it as being a AbstractDTO rather that a CategoryDTO in order to break the recursion. If I DO declare my parent as a CategoryDTO, the mapping works fine but I will get all of my parents and grand parents (which I do not want).

Anybody knows how I could fix this?

import java.util.UUID;

import org.junit.Assert;
import org.junit.Test;
import org.modelmapper.ModelMapper;

public class CategoryTest {

    public static class Category {
        private String uid = UUID.randomUUID().toString();
        private String name;
        private Category parent;

        public Category () {}

        public Category(String name, Category parent) {
            this.name = name;
            this.parent = parent;
        }

        public String getUid() {return uid;}
        public void setUid(String uid) {this.uid = uid;}
        public String getName() {return name;}
        public void setName(String name) {this.name = name;}
        public Category getParent() {return parent;}
        public void setParent(Category parent) {this.parent = parent;}
    }

    public static class AbstractDTO {
        private String uid;
        private String name;

        public String getUid() {return uid;}
        public void setUid(String uid) {this.uid = uid;}
        public String getName() {return name;}
        public void setName(String name) {this.name = name;}
    }

    public static class CategoryDTO extends AbstractDTO {
        private AbstractDTO parent;

        public AbstractDTO getParent() {return parent;}
        public void setParent(AbstractDTO parent) {this.parent = parent;}
    }

    @Test
    public void simpleTest() {
        Category dto = new Category("Test1",null);

        CategoryDTO entity = new ModelMapper().map(dto, CategoryDTO.class);

        Assert.assertEquals("Test1", entity.getName());
        Assert.assertEquals(dto.getUid(), entity.getUid());
    }

    @Test
    public void withParentTest() {
        Category dto = new Category("child",new Category("parent", new Category("root", null)));

        CategoryDTO entity = new ModelMapper().map(dto, CategoryDTO.class);

        Assert.assertEquals("child", entity.getName());
        Assert.assertEquals(dto.getUid(), entity.getUid());
        Assert.assertNotNull(entity.getParent()); // my child should have a parent dto
        Assert.assertTrue(entity.getParent() instanceof AbstractDTO); // and it should be an AbstractDTO to stop
    }
}

[Willix]

Ok
Solved it by adding the following method that I use to retrieve my ModelMapper

private ModelMapper getModelMapper() {
    ModelMapper map = new ModelMapper();
    map.addConverter(new AbstractConverter<Category, AbstractDTO>() {

        @Override
        protected AbstractDTO convert(Category source) {
            if (source == null) return null;
           
            AbstractDTO dto = new AbstractDTO();
            dto.setUid(source.getUid());
            dto.setName(source.getName());
            return dto;
        }
   
    });
    return map;
}

[Willix]

Ok solved it by adding the following method that I use to retrieve my ModelMapper

private ModelMapper getModelMapper() {
    ModelMapper map = new ModelMapper();
    map.addConverter(new AbstractConverter<Category, AbstractDTO>() {

        @Override
        protected AbstractDTO convert(Category source) {
            if (source == null) return null;
           
            AbstractDTO dto = new AbstractDTO();
            dto.setUid(source.getUid());
            dto.setName(source.getName());
            return dto;
        }
   
    });
    return map;
}

On Friday, December 11, 2015 at 10:20:03 AM UTC+1, Willix wrote: