I have trying to implement MapStruct mapping library. I have made samples and for simple mapping it works fine but I stucked in 1 issue.
I have 2 jpa entity classes which have two way relationships. One is in another and another is in one. It creates cyclic mapping issue so MapStruct throws StackOverflow error.
I have created minimal code to reproduce the case on github.
Sample code:
public class A {
private Long id;
private String name;
private B bData;
//getter-setter
}
public class B {
private Long id;
private String name;
private Set<A> aData;
//getter-setter
}
DataGenerator
public class DataGenerator {
public static A generateData(){
A a = new A();
a.setId(1L);
a.setName("foo");
B b = new B();
b.setId(2L);
b.setName("bar");
A a2 = new A();
a2.setId(3L);
a2.setName("john");
a2.setbData(b);
A a3 = new A();
a3.setId(4L);
a3.setName("doe");
a3.setbData(b);
Set<A> aData = new HashSet<A>();
aData.add(a2);
aData.add(a3);
b.setaData(aData);
a.setbData(b);
return a;
}
}
Mapper
#Mapper
public interface CustomMapper {
CustomMapper INSTANCE = Mappers.getMapper(CustomMapper.class);
ADto atoADto(A a);
}
App
public class AppMain {
public static void main(String[] args) {
A a = DataGenerator.generateData();
ADto aDto = CustomMapper.INSTANCE.atoADto(a);
System.out.println(aDto.getId());
}
}
Dto/Destination classes are same as original source classes.
The main is cyclic/recursive mapping issue which causes stackoverflow error.
Same thing working with spring BeanUtils.copyProperties but I want to implement MapStruct. Currently I am thinking to replace spring BeanUtils with MapStruct.
any suggestions?
See this mapstruct github issue for the solution, which is to ignore the field causing the recursion. I quote:
"You can achieve it with the #Qualifier. You can use #Named and qualifiedByName, or you can use your own custom #CountryWithoutCities qualifier with qualifiedBy.
Class country{
String id;
String name;
List<City> cities;
}
Class City{
String id;
String name;
Country country;
}
#Mapper(uses = CityMapper.class)
interface CountryMapper {
#Mapping( target = "cities", qualifiedByName = "noCountry")
CountryDto toDto(Country country);
#CountryWithoutCities
#Mapping( target = "cities", ignore = true)
CountryDto toDtoWithoutCities(Country country);
}
#Mapper(uses = CountryMapper.class)
interface CityMapper {
#Named( "noCountry" )
#Mapping( target = "country", ignore = true)
CityDto toDtoWithoutCountry(City city);
#Mapping( target = "country", qualifiedBy= CountryWithoutCities.class)
CityDto toDto(City city);
}
There's an example here in the MapStruct repo how to deal with cycles and recursion. Basically you need to keep track of state. The example makes use of a context object to do so.
Related
I am using spring data neo4j 6.1.3 and following is my use case code snippets
Domain Entity
#Data
#Node("DATspace")
public class DatSpace {
#Id #GeneratedValue
private Long neoId;
#Property("SUPtitle")
private String title;
private String SUPid;
}
Test class
#SpringBootTest
#EnableNeo4jRepositories(basePackages = "com.rahal.marvel")
public class ProjectionTest {
#Autowired
private Neo4jTemplate neo4jTemplate;
interface DATspaceProjection {
String getTitle();
String getSUPid();
}
#Test
public void test_projection(){
DatSpace d = neo4jTemplate.findOne("MATCH (s:DATspace {SUPid: $id}) RETURN s", Collections.singletonMap("id", "SPC_ML7"), DatSpace.class).get();
d.setTitle("title modified");
d.setSUPid("SUPid modified");
DATspaceProjection p = neo4jTemplate.saveAs(d, DATspaceProjection.class);
}
}
Ideally above saveAs function should modify both DATspace.SUPtitle and DATspace.SUPid. However it only modify SUPid but not SUPtitle. I presume it is due to property mapping (#Property) . Is this a bug or are there any workaround?
The provided #Property annotation does only have an impact on the annotated property (title) itself.
There is no knowledge right now that goes from the getTitle() method in the projection to the annotated title field in the domain class.
To be safe when modifying this use the explicit property name:
interface DATspaceProjection {
String getSUPtitle();
String getSUPid();
}
I created an issue for improvement https://github.com/spring-projects/spring-data-neo4j/issues/2371
I'm creating DTO versions of all my entities. I have a problem with an entity that has one Enum value. This is my entity:
#Getter
#Setter
#Table(name = "TIPOS_MOVIMIENTO")
#Entity
public class TipoMovimiento {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column
#Convert(converter = TipoMovEnumConverter.class)
private TipoMov tipo;
public String getTipo() {
return tipo.getTipoNombre();
}
#OneToMany(mappedBy = "tipoMov")
private List<Movimiento> movimientos;
No, I don't have #Enumerated because I followed a tutorial: "JPA 2.1 Attribute Converter – The better way to persist enums" and I had to remove it. I use a converter, as you can see.
This is my DTO of the previous entity:
#Getter
public class TipoMovimientoDto implements DtoEntity {
#Convert(converter = TipoMovEnumConverter.class) //I don't even know if write this here!!!!!
private TipoMov tipo;
}
The reason why I've followed that tutorial ↑ is because I wanted to write in database the variable values (tipoNombre) of enum (not enum name itself) because format. I want to store it in DB with accents, and I want to show it in Postman or whatever REST Client app with accents! Don't tell me anything about format it in front-end because this project is only back-end :(
Well, I think you will understand what I found with this with a image:
If you know a better way to do this, let me know, but this is not my problem now.
Let me show you the Enum:
public enum TipoMov {
INGRESO("Ingreso"),
PRESTAMO("Prestamo"),
PAGO("Pago"),
AMORTIZACION("Amortización"),
INTERES("Interés");
private String tipoNombre;
public String getTipoNombre() {
return tipoNombre;
}
TipoMov(String tipoNombre) {
this.tipoNombre = tipoNombre;
}
public static TipoMov fromDBName(String tipoNombre) {
switch (tipoNombre) {
case "Ingreso":
return TipoMov.INGRESO;
case "Préstamo":
return TipoMov.PRESTAMO;
case "Pago":
return TipoMov.PAGO;
case "Amortización":
return TipoMov.AMORTIZACION;
case "Interés":
return TipoMov.INTERES;
default:
throw new IllegalArgumentException("ShortName [" + tipoNombre
+ "] not supported.");
}
}
}
The problem is that I can't get the output in Postman if I convert this to DTO version. I get the appropiate output without DTO. I'm using REST services. Let me show you the services and controller.
(They include both versions, without DTO and with DTO (that is not working)).
ServiceImpl
#Service
public class TipoMovimientoServiceImpl implements TipoMovimientoService {
#Autowired
TipoMovimientoRepository repository;
#Autowired
DtoUtils dtoUtils;
public List<DtoEntity> findAllDto() {
List<TipoMovimiento> tiposMovimiento = repository.findAll();
List<DtoEntity> tiposMovimientoDto = new ArrayList();
for (TipoMovimiento tipoMovimiento : tiposMovimiento) {
DtoEntity tipoMovimientoDto= dtoUtils.convertToDto(tipoMovimiento, new TipoMovimientoDto());
tiposMovimientoDto.add(tipoMovimientoDto);
}
return tiposMovimientoDto;
}
public List<TipoMovimiento> findAll() {
List<TipoMovimiento> tiposMovimiento = repository.findAll();
return tiposMovimiento;
}
}
Service Interface
public interface TipoMovimientoService {
List<DtoEntity> findAllDto();
List<TipoMovimiento> findAll();
}
Controller:
#RestController
public class PruebasController {
#Autowired
TipoMovimientoService service;
#GetMapping("tiposmovdto")
public ResponseEntity <List <DtoEntity> > findAllDto() {
return ResponseEntity.ok(service.findAllDto());
}
#GetMapping("tiposmov")
public ResponseEntity <List <TipoMovimiento> > findAll() {
return ResponseEntity.ok(service.findAll());
}
}
As I said, the nonDto version works perfectly, but DTO version no. Is not the fault of DTO converter, because I have other REST services (that don't have enums) working perfectly with DTO. This is a problem about making compatible Enum and Dto!
I got it!!! I never thought this would work.
#Getter
public class TipoMovimientoDto implements DtoEntity {
private TipoMov tipo;
}
I just changed in the code above (Dto):
private TipoMov tipo;
to
private String tipo;
I can't explain how Enum from Entity could have been converted to DTO, using String instead Enum... But that worked!
In case you have the same problem... this is my Attribute Converter between Enum and String
#Converter(autoApply = true)
public class TipoMovEnumConverter implements AttributeConverter<TipoMov, String> {
public String convertToDatabaseColumn(TipoMov tipoMov) {
return tipoMov.getTipoNombre();
}
public TipoMov convertToEntityAttribute(String dbData) {
return dbData == null ? null : TipoMov.fromDBName(dbData);
}
}
Is still necessary to use it in Entity class, above of the enum variable:
#Convert(converter = TipoMovEnumConverter.class)
But not necessary in DTO. Just use String instead Enum in DTO!
Let's have source classes
#Data
public class Source {
private String name;
}
#Data
public class SourceParent {
private String parentName;
}
and target classes
#Data
public class Target {
private String name;
private TargetParent parent;
}
#Data
public class TargetParent {
private String parentName;
}
As you can see in Source I don't have the parent reference.
What I do is
Source s = findSource();
SourceParent sp = findParentForSource(s);
Target t = mapperFactory.map(s, Target.class);
mapperFactory.map(sp, t); //<--- Here is the problem
The problem is that I cannot map a SourceParent object to a specific field in Target.
I know how to do this using custom mappers or another "manual" ways. Is there a way to do it "Orika way"?
Something like:
mapperFactory.classMap(SourceParent.class, Target.class)
.fieldAtoB("?myslef?","parent")
.register();
Try with
mapperFactory.classMap(SourceParent.class, Target.class)
.fieldAtoB("","parent")
.register();
I have two classes:
public class A{
private String property;
private Set<B> bs = new HashSet<B>();
}
public class B{
private String property;
private A owner;
}
I created a basic JAX-RS + Spring boot application, and I want to return A.
Problem is that A contains a Set<B>, so I get an infinite nested level problem.
I found a solution: provide a link instead of the resource itself, this way I can have this:
{ "property" : "value", "bs" : "http://mywebsite/api/a/2/bs" }
And i don't get any nested level problem, since each level is serialized seperately.
How can I implement such a thing in my JAX-RS application? I found nothing about it but I know it's possible since Spring Data Neo4j REST is using it, and it works well.
I can think of the following possible ways how to achieve that.
Convert the set to URI during serialization by using a XmlAdapter
#XmlRootElement
public class A
{
private int id;
private String property;
#XmlJavaTypeAdapter(BsAdapter.class)
private Set<B> bs = new HashSet<B>();
}
public class BsAdapter extends XmlAdapter<URI, Set<B>>
{
#Override
public Set<B> unmarshal(URI v) throws Exception
{
return new HashSet<>();
}
#Override
public URI marshal(Set<B> v) throws Exception
{
return URI.create(
Optional.ofNullable(v)
.filter(b -> !b.isEmpty())
.map(b -> "/" + b.stream().findFirst().get().getOwner().getId() + "/bs")
.orElse(""));
}
}
If the id of A is part of the URI then it can only be retrieved if the set is not empty. The result is a relative URI, since there are no further information available.
As an alternative set the URI manually.
#XmlRootElement
#XmlAccessorType(XmlAccessType.FIELD)
public class A
{
private int id;
private String property;
#XmlTransient
private Set<B> bs = new HashSet<B>();
#XmlElement(name = "bs")
private URI bsUri;
}
And set the URL like this:
#Context
UriInfo uriInfo;
#GET
#Produces(MediaType.APPLICATION_JSON)
public Response getA()
{
// ...
a.setBsUri(UriBuilder.fromUri(uriInfo.getAbsolutePath())
.path("a")
.path("{id}")
.path("bs")
.build(2));
return Response.ok().entity(a).build();
}
Or if a link in HTTP Header is also fine, simply do it this way so you do not have to extend class A with the URI.
return Response.ok().entity(a).link(UriBuilder.fromUri(uriInfo.getAbsolutePath())
.path("a")
.path("{id}")
.path("bs")
.build(2), "bs").build();
I would like to put into db a class that have java.awt.geom.Point2D field. Is it possible?
Here is my code.
#Entity
#Table(name = "my_class_table")
public class MyClass {
private String aliasId;
private Point2D field;
public Point2D getField() {
return field;
}
public void setFieldPoint2D field) {
this.field = field;
}
public String getAliasId() {
return aliasId;
}
public void setAliasId(String aliasId) {
this.aliasId = aliasId;
}
}
And the reason of the exception which is thrown:
Could not determine type for: java.awt.geom.Point2D, at table: my_class_table, for columns: [org.hibernate.mapping.Column(field)]
Of course, the reason is quite obvious. My question is: how should I annotate the class to be able to use a field of Point2D class? Is it possible at all?
The simplest way is to use a java.awt.Point that extends Point2D and is a Serializable class. This way hibernate will automatically map it with SerializableType and you don't need to do anything more. The point object will be saved in its serialized form in a blob database table column.
You have also the option to define a custom hibernate type for the Point2D class. Here is a link of how to define a custom hibernate type.
You can't add annotations to existing classes.
But you can define a CompositeUserType to tell Hibernate how to map a Point2D.
Thanks guys for response. Unfortunatelly java.awt.Point class uses Integer, so it is useless in my case. The easiest way to solve it would be to use Point2D.Double which implements Serializable (but definition of UserType or CompositeUserType is more convenient if you don't want to change class definition). So, the simple solution:
#Entity
#Table(name = "my_class_table")
public class MyClass {
private String aliasId;
private Point2D.Double field;
public Point2D.Double getField() {
return field;
}
public void setField(Point2D.Double field) {
this.field = field;
}
public String getAliasId() {
return aliasId;
}
public void setAliasId(String aliasId) {
this.aliasId = aliasId;
}
}
But my final goal was to create a class with ordered list of points. If anybody is interested here is an example of the class representing line:
#Entity
public class Line {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "idDb", unique = true, nullable = false)
private int id;
#ElementCollection
#CollectionTable(name="points_table", joinColumns = #JoinColumn(name="idDb"))
#IndexColumn(name = "idx")
#Column(name="point_val")
private List<Point2D.Double> points = new ArrayList<Point2D.Double>();
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public List<Point2D.Double> getPoints() {
return points;
}
public void setPoints(List<Point2D.Double> points) {
this.points = points;
}
}