Lombok @Builder Model Class with field class and List Class

August 29, 2022

Im new to Spring and Im trying to create DTO with Lombok @Builder.
But i having trouble set up the data from field class take a look at addressDTO and childsDTO in ParentDTO class.

import java.util.List;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Parent {
    
    private String name;
    private Integer age;
    private Address address;
    private List<Child> childs;
}


import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Child {
    
    private String name;
    private Integer age;

}


import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Address {
    
    private Integer Zipcode;
    private String City;

}

DTO class

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ToString
public class ParentDTO {
    
    private String nameDTO;
    private Integer ageDTO;
    private AddressDTO addressDTO;
    private List<ChildDTO> childsDTO;
    
    public static ParentDTO convertParentDTO(Parent parent) {
        return ParentDTO.builder()
                .nameDTO(parent.getName())
                .ageDTO(parent.getAge())
                .addressDTO( null) // i try this wont work .addressDTO(parent.getAddress()) .addressDTO( AddressDTO::connerAddressDTO)) 
                .childsDTO(null) // i try this .childsDTO(List.of()) then ?
                .build();
    }

}


import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ToString
public class ChildDTO {
    
    private String nameDTO;
    private Integer ageDTO;
    
    public static ChildDTO convertChildDTO(Child child) {
        return ChildDTO.builder()
                .nameDTO(child.getName())
                .ageDTO(child.getAge())
                .build();
    }

}


import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ToString
public class AddressDTO {
    
    private Integer ZipcodeDTO;
    private String CityDTO;
    
    public static AddressDTO connerAddressDTO(Address address) {
        return AddressDTO.builder()
                .ZipcodeDTO(address.getZipcode())
                .CityDTO(address.getCity())
                .build();
    }

}

>Solution :

If I understand well the question it’s should be like this.

import lombok.*;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ToString
public class ParentDTO {
    private String nameDTO;
    private Integer ageDTO;
    private AddressDTO addressDTO;
    private List<ChildDTO> childsDTO;

    public static ParentDTO convertParentDTO(Parent parent) {
        return ParentDTO.builder()
            .nameDTO(parent.getName())
            .ageDTO(parent.getAge())
            .addressDTO(
                 AddressDTO.connerAddressDTO(
                     parent.getAddress()))
            .addressDTO(parent.getAddress())
            .childsDTO(toChildrenDto(parent.getChilds()))
         .build();
    }

    private static List<ChildDTO> toChildrenDto(List<Child> children) {
        if (children == null || children.isEmpty()) {
            return Collections.emptyList();
        }
        return children.stream()
                .map(c -> 
             ChildDTO.builder().ageDTO(c.getAge()).nameDTO(c.getName()).build())
      .collect(Collectors.toList());
    }
}