I'm new to Neo4J and I have, probably an easy question.
There're NodeEntitys in my application, a property (name) is annotated with #Indexed(unique = true) to achieve the uniqueness like I do in JPA with #Column(unique = true).
My problem is, that when I persist an entity with a name that already exists in my graph, it works fine anyway.
But I expected some kind of exception here...?!
Here' s an overview over basic my code:
#NodeEntity
public abstract class BaseEntity implements Identifiable
{
#GraphId
private Long entityId;
...
}
public class Role extends BaseEntity
{
#Indexed(unique = true)
private String name;
...
}
public interface RoleRepository extends GraphRepository<Role>
{
Role findByName(String name);
}
#Service
public class RoleServiceImpl extends BaseEntityServiceImpl<Role> implements
{
private RoleRepository repository;
#Override
#Transactional
public T save(final T entity) {
return getRepository().save(entity);
}
}
And this is my test:
#Test
public void testNameUniqueIndex() {
final List<Role> roles = Lists.newLinkedList(service.findAll());
final String existingName = roles.get(0).getName();
Role newRole = new Role.Builder(existingName).build();
newRole = service.save(newRole);
}
That's the point where I expect something to go wrong!
How can I ensure the uniqueness of a property, without checking it for myself??
P.S.: I'm using neo4j 1.8.M07, spring-data-neo4j 2.1.0.BUILD-SNAPSHOT and Spring 3.1.2.RELEASE.
I walked into the same trap... as long as you create new entities, you will not see the exception - the last save()-action wins the battle.
Unfortunately, the DataIntegrityViolationException will be raised only in case of update an existing entity!
A detailed description of that behaviour can be found here:
http://static.springsource.org/spring-data/data-graph/snapshot-site/reference/html/#d5e1035
If you are using SDN 3.2.0+ use the failOnDuplicate attribute:
public class Role extends BaseEntity
{
#Indexed(unique = true, failOnDuplicate = true)
private String name;
...
}
Related
I'm new to Mapstruct and I'm trying to understand it properly.
What I want to achieve is converting from a DTO String parameter (carModel) to his Entity, retrieve using Service and Repository.
The problem is that Mapper class generated by Mapstruct is trying to inject the Service class with #Autowired annotation, but it's not working. The service is null.
Here's my #Mapper class:
#Mapper(componentModel = "spring", uses = CarModelService.class)
public interface KitMapper extends EntityMapper<KitDTO, Kit> {
KitMapper INSTANCE = Mappers.getMapper(KitMapper.class);
#Mapping(source = "weight", target = "systemWeight")
#Mapping(source = "carModel", target = "carModel")
Kit toEntity(KitDTO kitDTO);
}
public interface EntityMapper<D, E> {
E toEntity(D dto);
List<E> toEntity(List<D> dtoList);
}
The #Service class:
#Service
#Transactional
public class CarModelService {
private final CarModelRepository carModelRepository;
#Transactional(readOnly = true)
public CarModel findByName(String name) {
return carModelRepository.findByName(name).orElse(null);
}
}
The #Repository class:
#Repository
public interface CarModelRepository extends JpaRepository<CarModel, Long> {
Optional<CarModel> findByName(String carModelName);
}
The DTO and Entity classes:
public class KitDTO {
private String id;
private String carModel; // e.g. "Ferrari Monza"
....
}
#Entity
#Table(name = "kit")
public class Kit implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
#SequenceGenerator(name = "sequenceGenerator")
#Column(name = "id")
private Long id;
#ManyToOne
private CarModel carModel;
...
}
#Entity
#Table(name = "car_model")
public class CarModel implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
#SequenceGenerator(name = "sequenceGenerator")
#Column(name = "id")
private Long id;
#Column(name = "name")
private String name;
...
}
The build work properly but the application stop when I try to use the Mapper. It says that carModelService is null.
Here's the mapper generated implementation class:
#Component
public class KitMapperImpl implements KitMapper {
#Autowired // <-- this seems not working
private CarModelService carModelService;
#Override
public Kit toEntity(KitDTO kitDTO) {
if ( kitDTO == null ) {
return null;
}
Kit kit = new Kit();
kit.setSystemWeight( String.valueOf( kitDTO.getWeight() ) );
kit.carModel( carModelService.findByName(kitDTO.getCarModel()) ); // <-- carModelService is null!
// other setters
return kit;
}
}
I've tried many things, using Decorator, #Context, expression, inject the #Mapper class into the #Service class.
I've found many questions but actually no one helped me:
Mapstruct - How can I inject a spring dependency in the Generated Mapper class
#Service Class Not Autowired in org.mapstruct.#Mapper Class
MapStruct mapper not initialized with autowired when debug
Any help would be appreciated! Thanks in advance!
Found the solution!
Instead of calling directly the Mapper method toEntity() from the #RestController class, I injected the mapper in the CarModelService class and created a method that call the mapper.
In this way the flow is:
Controller --> Service --> Mapper
#Service
#Transactional
public class KitService {
private final KitRepository kitRepository;
private final KitSearchRepository kitSearchRepository;
private final KitMapper kitMapper; // <-- mapper declaration
public KitService(KitRepository kitRepository, KitSearchRepository kitSearchRepository, KitMapper kitMapper) {
this.kitRepository = kitRepository;
this.kitSearchRepository = kitSearchRepository;
this.kitMapper = kitMapper; // <-- mapper initilization
}
// here the method which calls mapper
public Kit convertDTOToEntity(KitDTO kitDTO) {
return kitMapper.toEntity(kitDTO);
}
In this way, the generated class by Mapstruct doesn't give error on the CarModelService.
Seems like this approach is the only way to achieve this, create a king of "bridge" between services and mappers.
(You can use also the #Autowired annotation instead of constructor)
Can you please share the error message?
From the information that you shared, I can see the carModel in KitDto is String and in Entity is CarModel class. Not sure how mapstruct's auto generated implementation class implemented this: kit.carModel( carModelService.findByName(kitDTO.getCarModel()) );.
But I would like to share another approach,Don't know this is a best practice or not. In this approach you can create a abstarct class of mapper, in which you can #Autowired repository can manually add those mapping.
I shared the snippet for it. Hopefully this will help you.
#Mapper(componentModel = "spring", nullValuePropertyMappingStrategy = NullValuePropertyMappingStrategy.IGNORE)
public abstract class ProductMapper {
#Autowired
private CarModelService carModelService;
public abstract Kit convertDTOToEntity(KitDTO kitDTO);
public Kit toEntity(KitDTO kitDTO);
{
Kit kit = convertDTOToEntity(kitDTO);
kit.setCarModel(carModelService.findByName(kitDTO.getCarModel()));
return kit;
}
}
Curious about the other approaches, will follow this thread. We can discuss the best practices
I am using simple relationship (spring data elasticsearch) but springboot is throwing StackOverflowError
#Document(indexName = "users", type = "user")
public class User {
#Id
private String id;
#Field(type= FieldType.Nested,ignoreFields={"users"})
private Set<Group> groups = new HashSet<Group>();
}
#Document(indexName = "groups", type = "group")
public class Group {
#Id
String id;
#Field(type = FieldType.Nested, ignoreFields ={"groups"})
private Set<User> users = new HashSet<User>();
}
public interface UserRepository extends ElasticsearchRepository<User, String>{
}
public interface GroupRepository extends ElasticsearchRepository<Group, String> {
}
Any Idea what is problem?
Code is from https://github.com/spring-projects/spring-data-elasticsearch/tree/master/src/test/java/org/springframework/data/elasticsearch/entities
Thanks
Rajan
As you said: spring-boot is throwing StackOverflowError.
It's because of no safeguards or detecting circular dependencies in spring-boot.
Look at spring-boot source: MappingBuilder.java, there's loop that will never break when you have class A that have a #Field annotation referencing class B, that have #Field annotation referencing class A.
Does anyone have any idea how to get a single column using Spring Data JPA? I created a repository like below in my Spring Boot project, but always get the {"cause":null,"message":"PersistentEntity must not be null!"} error when accessing the Restful URL.
#RepositoryRestResource(collectionResourceRel = "users", path = "users")
public interface UsersRepository extends CrudRepository<Users, Integer> {
#Query("SELECT u.userName FROM Users u")
public List<String> getUserName();
}
Then if I access the Restful URL like ../users/search/getUserName, I get the error:
{"cause":null,"message":"PersistentEntity must not be null!"}
Create a Projection interface
public interface UserNameOnly {
String getUserName();
}
Then in your repository interface return that type instead of the user type
public interface UserRepository<User> extends JpaRepository<User,String> {
List<UsernameOnly> findNamesByUserNameNotNull();
}
The get method in the projection interface must match a get method of the defined type on the JPA repository, in this case User.
The "findBySomePropertyOnTheObjectThatIsNotNull" allows you to get a List of the entities (as opposed to an Iterable) based on some criteria, which for a findAll can simply be if the unique identifier (or any other NonNull field) is not null.
Concept is : In your entity class create a constructor with only required instant variables. And use that constructor in the repository method shown below.
Lets say you have a interface Repository like below
Repository implementation:
public interface UserRepository<User> extends JpaRepository<User,String>
{
#Query(value = "select new com.org.User(usr.userId) from User usr where usr.name(:name)")
List<User> findUserIdAlone(#Param("name") String user);
}
In Controller
#RestController
public class UserController
{
#Autowired
private UserRepository<User> userRepository;
#Res
public ResponseEntity<User> getUser(#PathVariable("usrname") String userName)
{
User resultUser = usrRepository.findUserIdAlone(userName);
return ResponseEntity.ok(resultUser);
}
}
public class User
{
private String userId,userName;
public User(String userId)
{
this.userId=userId;
}
// setter and getters goes here
}
This Works for me.
public interface UserDataRepository extends JpaRepository<UserData, Long> {
#Query(value = "SELECT emp_name FROM user_data", nativeQuery = true)
public List<Object[]> findEmp_name();
}
System.out.println("data"+ userDataRepository.findEmp_name());
The above line gave me this result :
data[abhijeet, abhijeet1, abhijeet2, abhijeet3, abhijeet4, abhijeet5]
If you want to only return a single column you should look at Projections and Excerpts which will allow you to filter specific columns and other things that are usefule.
If you need list all of the users, try select userName from Users, if you need one user use "where" look at spring data JPA http://docs.spring.io/spring-data/jpa/docs/current/reference/html/ , try change CrudRepository to JpaRepository
It is possible to provide custom implementations of methods in a Spring Data JPA repository, which enables complete control on queries and return types. The approach is as follows:
Define an interface with the desired method signatures.
Implement the interface to achieve the desired behavior.
Have the Repository extend both JpaRepository and the custom interface.
Here is a working example that uses JpaRepository, assuming a user_table with two columns, user_id and user_name.
UserEntity class in model package:
#Entity
#Table(name = "user_table")
public class UserEntity {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name = "user_id")
private Long userId;
#Column(name = "user_name")
private String userName;
protected UserEntity() {}
public UserEntity(String userName) {
this.userName = userName;
// standard getters and setters
}
Define interface for the custom repository in the repository package:
public interface UserCustomRepository {
List<String> findUserNames();
}
Provide implementation class for the custom interface in the repository package:
public class UserCustomRepositoryImpl implements UserCustomRepository {
// Spring auto configures a DataSource and JdbcTemplate
// based on the application.properties file. We can use
// autowiring to get a reference to it.
JdbcTemplate jdbcTemplate;
#Autowired
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
// Now our custom implementation can use the JdbcTemplate
// to perform JPQL queries and return basic datatypes.
#Override
public List<String> findUserNames() throws DataAccessException {
String sql = "SELECT user_name FROM user_table";
return jdbcTemplate.queryForList(sql, String.class);
}
}
Finally, we just need to have the UserRepository extend both JpaRepository and the custom interface we just implemented.
public interface UserRepository extends JpaRepository<UserEntity, Long>, UserCustomRepository {}
Simple test class with junit 5 (assuming the database is initially empty):
#SpringBootTest
class UserRepositoryTest {
private static final String JANE = "Jane";
private static final String JOE = "Joe";
#Autowired
UserRepository repo;
#Test
void shouldFindUserNames() {
UserEntity jane = new UserEntity(JANE);
UserEntity joe = new UserEntity(JOE);
repo.saveAndFlush(jane);
repo.saveAndFlush(joe);
List<UserEntity> users = repo.findAll();
assertEquals(2, users.size());
List<String> names = repo.findUserNames();
assertEquals(2, names.size());
assertTrue(names.contains(JANE));
assertTrue(names.contains(JOE));
}
}
I have an entity which would be stored in both relational(MySql) and graph database(Neo4j).
#Entity
#NodeEntity(partial = true)
public class User {
#NotNull
#Column(name = "UserName", unique = true)
private String userName;
#GraphProperty
String firstName;
}
I know we have JpaRepository and GraphRepository.
public interface UserRepository extends JpaRepository<User, Long> { }
public interface UserGraphRepository extends GraphRepository<User> { }
But is there any repository implementation for handling such a cross store entity? So I could do something like this.
public interface UserRepository extends CrossStoreRepository<User, Long> { }
So when I call save, it should save in both the databases.
I did some searching and found nothing.So started writing one myself.
If no such thing exist, is there a plan to add one in the future?
Is there any reason why you can't use spring-data-neo4j-cross-store as it is part of the spring-data-neo4j distribution?
I'm experiencing some strange behavior when I'm looking up node entities with Spring Data Neo4j (SDN). If I use GraphRepository.findOne(long) it will return an entity with that identifier even though the entity is not of the same type.
This is what my (very) simplified entity structure looks like:
#NodeEntity
protected abstract class BaseEntity {
#GraphId
private Long id;
#JsonIgnore
#RelatedTo(type = RelationType.ENTITY_AUDIT)
private Audit audit;
}
#NodeEntity
public final class Person extends BaseEntity {
#Indexed(indexType = IndexType.FULLTEXT)
private String firstName;
#Indexed(indexType = IndexType.FULLTEXT)
private String lastName;
}
#NodeEntity
public class Audit extends BaseEntity {
#RelatedTo(type = RelationType.ENTITY_AUDIT, direction = Direction.INCOMING)
private BaseEntity parent;
private Long date;
private String user;
}
For every entity type, I've created repositories like this:
#Repository
public interface PersonRepository extends GraphRepository<Person> {}
#Repository
public interface AuditRepository extends GraphRepository<Audit> {}
I've got an abstract base class for my service layer classes. That is what they roughly look like:
public abstract class MyServiceImpl<T extends BaseEntity> implements MyService<T> {
private GraphRepository<T> repository;
public MyServiceImpl(final GraphRepository<T> repository) {
this.repository = repository;
}
#Override
public T read(final Long identifier) throws EntityNotFoundException {
return repository.findOne(identifier);
}
#Override
public T create(final T entity) {
return repository.save(entity);
}
}
#Service
public class PersonServiceImpl extends MyServiceImpl<Person> implements PersonService {
private PersonRepository personRepository;
#Autowired
public PersonServiceImpl(final PersonRepository personRepository) {
super(personRepository);
this.personRepository = personRepository;
}
}
When I execute the following code, the result is not as expected:
Person person = new Person();
person.setFirstName("Test");
person.setLastName("Person");
personService.create(person);
// suppose the person identifier is 1L
final Audit audit = auditRepository.findOne(1L);
You'd expect that the AuditRepository would return null, but this in not the case. Instead, it returns an Audit with identifier 1L and null in all of its properties. It seems that as long as there's a node that corresponds to a given identifier, it will be returned, no mather what its type is. If Person and Audit would have had matching property names, they would contain their values too... Is all this expected behavior, or am I missing something?
For now, I've solved this problem with the code below, where I do the type check myself.
public abstract class MyServiceImpl<T extends BaseEntity> implements MyService<T> {
private GraphRepository<T> repository;
public MyServiceImpl(final GraphRepository<T> repository) {
this.repository = repository;
}
#Override
public T read(final Long identifier) throws EntityNotFoundException {
return get(identifier);
}
protected T get(final Long identifier) throws EntityNotFoundException {
final T entity = repository.findOne(identifier);
final Class<T> type = getServiceType();
if (entity == null || !(type.equals(repository.getStoredJavaType(entity)))) {
throw new EntityNotFoundException(type, identifier);
}
return entity;
}
#SuppressWarnings("unchecked")
private Class<T> getServiceType() {
return (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass())
.getActualTypeArguments()[0];
}
}
If you need more configuration, please let me know.
My framework versions are:
<spring.version>3.2.0.RC1</spring.version>
<neo4j.version>1.8</neo4j.version>
<spring.data.neo4j.version>2.1.0.RELEASE</spring.data.neo4j.version>
we had that behavior before that it failed on the wrong entity type being returned, we changed that behavior so that the type you provide is used to automatically project the node to.
public <S extends PropertyContainer, T> T createEntityFromStoredType(S state, MappingPolicy mappingPolicy) {..}
template. createEntityFromStoredType(node, null) will get you the object with the stored state.
public Class getStoredJavaType(Object entity) {}
gives you the stored class for a node or relationship (or entity)
We had a discussion of changing the behavior back and failing esp. in Repositories.
The question is, what should happen then? An Exception? A Null result? ...
In general if you provide a raw node-id that is valid, returning an error or Null doesn't seem to be like a correct answer either?