Modelmapper circular mapping - modelmapper

Question

I've parent and child class with respective DTO's as follows
class Parent {
List<Child> children;
// setters and getters
}
class Child {
Parent parent;
}
class ParentDto {
List<ChildDto> children;
// setters and getters
}
class ChildDto {
ParentDto parent;
// setters and getters
}
When I try to map Parent to ParentDto I'm getting StackOverflowError.
Please help me in resolving the issue.

Answer 1

I know this post is old but I will try to give one answer in case someone from google to arrived here.
Probably you have a dynamic object creation.
Recently I had a problem like this. In my case I have a class Student that extends Person. And Person has three others attributes of type Person: father, mother and responsible. In case, I had a circularity relationship. When I ran my JUnits tests I got a circularity calls. I did't get a stakOverflow because the Spring (after some time) closes the data base connections.
I resolved this problem removing the dynamics objects creations from my Person class.
Another approach to solve this problem is adding a Condition in your mapper. You can read more about conditions here. For example, you can have some Conditions saying: "If the person attribute id is 10, then, doesn't need map it.". This way we can avoid infinity mapping.
Well, let's see some snippeds of code:
Student class:
public class Student extends Person implements IStudent {
private Person financialResponsible;
// Getters and setters.
}
Person class:
public class Person implements IPerson {
private Long id;
private String name;
private Person father;
private Person mother;
private Person responsible;
private Address address;
// Getters and setters.
// This is my real problem. I removed it and the mapper worked.
public IPerson getFather() {
if (father == null) father = new Person();
return father;
}
}
StudentDTO class:
public class StudentDTO extends PersonDTO {
private PersonDTO financialResponsible;
// Getters and setters.
}
PersonDTO class:
public class PersonDTO {
private Long id;
private String name;
private PersonDTO father;
private PersonDTO mother;
private PersonDTO responsible;
private AddressDTO address;
// Getters and setters.
}
Here is a example of conditions:
...
import org.modelmapper.Condition;
...
ModelMapper mapper = new ModelMapper();
// Define STRICT to give high precision on mapper.
mapper.getConfiguration().setMatchingStrategy(MatchingStrategies.STRICT);
/*
* Create conditions to avoid infinity circularity.
*/
// Condidions.
final Condition<IStudent, StudentDTO> fatherIsTen = mappingContext -> mappingContext.getSource().getFather().getId() == 10;
final Condition<IStudent, StudentDTO> motherIsTen = mappingContext -> mappingContext.getSource().getMother().getId() == 10;
final Condition<IStudent, StudentDTO> resposibleIsTen = mappingContext -> mappingContext.getSource().getResponsible().getId() == 10;
// Adding conditions on mapper.
mapper.createTypeMap(IStudent.class, StudentDTO.class) //
.addMappings(mapper -> mapper.when(fatherIsTen).skip(StudentDTO::setFather))
.addMappings(mapper -> mapper.when(motherIsTen).skip(StudentDTO::setMother))
.addMappings(mapper -> mapper.when(resposibleIsTen).skip(StudentDTO::setResponsible));
I hope help o/