I am building a simple REST service using spring. I separated my entities from DTOs and I made the DTOs immutable using Immutables. I needed mapping between DTOs and DAOs, so I chose MapStruct. The Mapper is not able to detect the setters I have defined in my DAOs.
The problem is exactly similar to this question. This question does not have an accepted answer and I have tried all of the suggestions in that question and they don't work. I don't want to try this answer because I feel it defeats the purpose for which I am using Immutables. @marc-von-renteln summarizes this reason nicely in the comment here
I tried the answer provided by @tobias-schulte. But that caused a different problem. In the Mapper class in the answer, trying to return Immutable*.Builder from the mapping method throws an error saying the Immutable type cannot be found.
I have exhaustively searched issues logged against MapStruct and Immutables and I haven't been able to find a solution. Unfortunately there are hardly few examples or people using a combination of MapStruct and Immutables. The mapstruct-examples repository also doesn't have an example for working with Immutables.
I even tried defining separate Mapper interfaces for each of the DtTOs (like UserStatusMapper). I was only making it more complicated with more errors.
I have created a sample spring project to demonstrate the problem. GitHub Repo Link. This demo app is almost same as the REST service I am creating. All database (spring-data-jpa , hibernate) stuff is removed and I am using mock data. If you checkout the project and run the demo-app you can make two API calls.
GetUser: Request: http://localhost:8080/user/api/v1/users/1 Response:
{
"id": 0,
"username": "TestUser",
"email": "TestUser@demo.com",
"userStatus": {
"id": 1,
"status": 1,
"statusName": "Active"
}
Createuser: PROBLEM HERE http://localhost:8080/user/api/v1/users/create Sample Input:
{
"username": "TestUser",
"email": "TestUser@demo.com",
"userStatus": {
"id": 1,
"status": 1,
"statusName": "Active"
}
}
Response:
{
"timestamp": "2019-04-28T09:29:24.933+0000",
"status": 500,
"error": "Internal Server Error",
"message": "Type definition error: [simple type, class com.immutablesmapstruct.demo.dto.model.ImmutableUserDto$Builder]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.immutablesmapstruct.demo.dto.model.ImmutableUserDto$Builder`, problem: Cannot build UserDto, some of required attributes are not set [username, email, userStatus]\n at [Source: (PushbackInputStream); line: 9, column: 1]",
"path": "/user/api/v1/users/create"
}
Below are important pieces of code related to problem:
Daos: 1. UserDao
public class User {
// Primary Key. Something that is annotated with @Id
private int id;
private String username;
private String email;
private UserStatus userStatus;
private User(Builder builder) {
id = builder.id;
username = builder.username;
email = builder.email;
userStatus = builder.userStatus;
}
public static Builder builder() {
return new Builder();
}
public int getId() {
return id;
}
public String getUsername() {
return username;
}
public String getEmail() {
return email;
}
public UserStatus getUserStatus() {
return userStatus;
}
public static final class Builder {
private int id;
private String username;
private String email;
private UserStatus userStatus;
private Builder() {
}
public Builder setId(int id) {
this.id = id;
return this;
}
public Builder setUsername(String username) {
this.username = username;
return this;
}
public Builder setEmail(String email) {
this.email = email;
return this;
}
public Builder setUserStatus(UserStatus userStatus) {
this.userStatus = userStatus;
return this;
}
public User build() {
return new User(this);
}
2. UserStatusDao:
package com.immutablesmapstruct.demo.dao.model;
/**
* Status of user.
* Example: Active or Inactive
*/
public class UserStatus {
// Primary Key. Something that is annotated with @Id
private int id;
// A value of 1 or 0
private int status;
// Active , InActive
private String statusName;
private UserStatus(Builder builder) {
id = builder.id;
status = builder.status;
statusName = builder.statusName;
}
public static Builder builder() {
return new Builder();
}
public int getId() {
return id;
}
public int getStatus() {
return status;
}
public String getStatusName() {
return statusName;
}
public static final class Builder {
private int id;
private int status;
private String statusName;
private Builder() {
}
public Builder setId(int id) {
this.id = id;
return this;
}
public Builder setStatus(int status) {
this.status = status;
return this;
}
public Builder setStatusName(String statusName) {
this.statusName = statusName;
return this;
}
public UserStatus build() {
return new UserStatus(this);
}
}
}
DTOs 1. UserDto:
package com.immutablesmapstruct.demo.dto.model;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import org.immutables.value.Value;
@Value.Immutable
@Value.Style(defaults = @Value.Immutable(copy = false), init = "set*")
@JsonSerialize(as = ImmutableUserDto.class)
@JsonDeserialize(builder = ImmutableUserDto.Builder.class)
public abstract class UserDto {
@Value.Default
@JsonProperty
public int id() {
return 0;
}
@JsonProperty
public abstract String username();
@JsonProperty
public abstract String email();
@JsonProperty
public abstract UserStatusDto userStatus();
2. UserStatusDto:
package com.immutablesmapstruct.demo.dto.model;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import org.immutables.value.Value;
@Value.Immutable
@Value.Style(defaults = @Value.Immutable(copy = false), init = "set*")
@JsonSerialize(as = ImmutableUserStatusDto.class)
@JsonDeserialize(builder = ImmutableUserStatusDto.Builder.class)
public abstract class UserStatusDto {
@JsonProperty
public abstract int id();
@JsonProperty
public abstract int status();
@JsonProperty
public abstract String statusName();
}
MapStruct UserMapper:
package com.immutablesmapstruct.demo.dto.mapper;
import com.immutablesmapstruct.demo.dao.model.User;
import com.immutablesmapstruct.demo.dao.model.UserStatus;
import com.immutablesmapstruct.demo.dto.model.UserDto;
import com.immutablesmapstruct.demo.dto.model.UserStatusDto;
import org.mapstruct.Mapper;
import org.mapstruct.factory.Mappers;
@Mapper(componentModel = "spring")
public interface UserMapper {
UserMapper USER_MAPPER_INSTANCE = Mappers.getMapper(UserMapper.class);
UserDto userDaoToDto(User user);
//Problem here.
User userDtoToDao(UserDto userDto);
UserStatusDto userStatusDaoToDto(UserStatus userStatusDao);
UserStatus userStatusDtoToDao(UserStatusDto userStatusDto);
}
If I look at the concrete method generated by MapStruct for userDtoToDao I can clearly see that the setters are not being recognized.
package com.immutablesmapstruct.demo.dto.mapper;
@Generated(
value = "org.mapstruct.ap.MappingProcessor",
date = "2019-04-28T02:29:03-0700",
comments = "version: 1.3.0.Final, compiler: javac, environment: Java 1.8.0_191 (Oracle Corporation)"
)
@Component
public class UserMapperImpl implements UserMapper {
...
...
@Override
public User userDtoToDao(UserDto userDto) {
if ( userDto == null ) {
return null;
}
com.immutablesmapstruct.demo.dao.model.User.Builder user = User.builder();
return user.build();
}
....
....
}
Mapstruct doesn't recognize your getters in UserDto and UserStatusDto.
When you change the existing methods (like public abstract String username()) in these abstract classes to classic getters like
@JsonProperty("username")
public abstract String getUsername();
the MapperImpl will contain the required calls. Note, that the @JsonProperty needs to have the attributes name itself afterwards (because of the changed method name).
Here are the complete classes UserDto and UserStatusDto with said changes:
package com.immutablesmapstruct.demo.dto.model;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import org.immutables.value.Value;
@Value.Immutable
@Value.Style(defaults = @Value.Immutable(copy = false), init = "set*")
@JsonSerialize(as = ImmutableUserDto.class)
@JsonDeserialize(builder = ImmutableUserDto.Builder.class)
public abstract class UserDto {
@Value.Default
@JsonProperty("id")
public int getId() {
return 0;
}
@JsonProperty("username")
public abstract String getUsername();
@JsonProperty("email")
public abstract String getEmail();
@JsonProperty("userStatus")
public abstract UserStatusDto getUserStatus();
}
package com.immutablesmapstruct.demo.dto.model;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import org.immutables.value.Value;
@Value.Immutable
@Value.Style(defaults = @Value.Immutable(copy = false), init = "set*")
@JsonSerialize(as = ImmutableUserStatusDto.class)
@JsonDeserialize(builder = ImmutableUserStatusDto.Builder.class)
public abstract class UserStatusDto {
@JsonProperty("id")
public abstract int getId();
@JsonProperty("status")
public abstract int getStatus();
@JsonProperty("statusName")
public abstract String getStatusName();
}