Map Recursive Link Between Two Objects

[Collin Molnar]

I'm trying to map a DTO to an Entity with a link to a list of parameters that links back to the entity. 

However, it creates a new Foo object in the FooParameter as the variable foo instead of setting foo to the same object that contains the List of FooParameters. 

I have tried, but this didn't do anything. 

ModelMapper fooMapper = new ModelMapper();
fooMapper.typeMap(FooDto.class, Foo.class).addMappings(map -> {
map.map(FooDto::getFooParameters, Foo::setParameters);
});

I think I have to use streams to point each parameter to the Foo object that holds them, but I'm not sure how to do this. 

Here is a simplified example of the two entity classes and DTOs. 

@Entity
public class Foo {
  @Id
  private Integer id;

  @OneToMany(fetch = FetchType.LAZY, mappedBy = "foo", cascade = CascadeType.ALL)

  private List<FooParameter> params;

}

@Entity
public class FooParameter {
  @EmbeddedId
  private FooParameterId cid;

  @ManyToOne(fetch = FetchType.LAZY, optional = false)
  private Foo foo;

  private String value; 

}

The DTOs are as follows

public class FooDto {

  private Integer id;

  private List<FooParameterDto> params;

}

public class FooParameterDto {

  private Integer fooId;

  private String value;

}