I have a class in my domain called Activity that looks like the following
#JsonIdentityInfo(generator=ObjectIdGenerators.PropertyGenerator.class, property="id")
#NodeEntity
public class Activity {
#GraphId
private Long id;
private String title;
private String description;
#Relationship(type = "RELATED_TO", direction = Relationship.UNDIRECTED)
private List<Activity> relatedActivities = new ArrayList<>();
public Activity() {
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public String getDescription() {
return description;
}
public Collection<Activity> getRelatedActivities() {
System.out.println("getting relatedActivities");
System.out.println(relatedActivities);
return relatedActivities;
}
public void addRelatedActivity(Activity activity) {
this.relatedActivities.add(activity);
}
}
I create relationships using the following repository class:
#RepositoryRestResource(collectionResourceRel = "relationships", path = "relationships")
public interface RelationshipRepository extends GraphRepository<Relationship> {
#Query("MATCH (a1:Activity), (a2:Activity) " +
"WHERE a1.title = {0} AND a2.title = {1}" +
"CREATE (a1)-[:RELATED_TO]->(a2)")
void addRelationship(String a1Title, String a2Title);
}
I have verified that this code works using the neo4j browser, which lets me see existing nodes and relationships between them. However, when I access getRelatedActivities() on an Activity object, it's always an empty array, even if that Activity has other Activity nodes related to it, clearly visible in neo4j.
How can I get the relatedActivites on an Activity to automatically populate based on its relationships correctly?
The problem in your code is that you define the "target" as an Activity here
#Relationship(type = "RELATED_TO", direction = Relationship.UNDIRECTED)
private List<Activity> relatedActivities = new ArrayList<>();
but you also have a RelationshipEntity class in your code base: Relationship with the same type RELATED_TO.
When OGM gets the result it tries to match every field but since it converts the relationship type RELATED_TO to the RelationshipEntity and not an Activity object, it does not fill the list in the Activity class.
Related
I am using spring JPA to attempt to write records to a postGres DB. At the time of the commit, I am getting the following error:
Caused by: org.postgresql.util.PSQLException: ERROR: null value in column "col_id" violates not-null constraint
Detail: Failing row contains (null, null, null, null, null)
I have the following repository interface:
public interface MyRepo extends JpaRepository <MyModel, String> {
}
, the following model class:
#Entity
#Validated
#Table(name = "my_table", schema="common")
public class MyModel {
#Id
#Column(name = "col_id")
private String id;
#Column(name = "second_col")
private String secCol;
#Column(name = "third_col")
private String thirdCol;
#Column(name = "fourth_col")
private String fourthCol;
#Column(name = "fifth_col")
private String fifthCol;
public MyModel() {
}
public MyModel(String id, String secCol, String thirdCol, String fourthCol, String fifthCol) {
this.id = id;
this.secCol = secCol;
this.thirdCol = thirdCol;
this.fourthCol = fourthCol;
this.fifthCol = fifthCol;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getSecCol() {
return secCol;
}
public void setSecCol(String secCol) {
this.secCol = secCol;
}
public String getThirdCol() {
return thirdCol;
}
public void setThirdCol(String thirdCol) {
this.thirdCol = thirdCol;
}
public String getFourthCol() {
return fourthCol;
}
public void setFourthCol(String fourthCol) {
this.fourthCol = fourthCol;
}
public String getFifthCol() {
return fifthCol;
}
public void setFifthCol(String fifthCol) {
this.fifthCol = fifthCol;
}
}
, and the relevant part of the service class:
public MyModel myModel (MyModel myModel) {
MyModel mm = null;
try {
mm = myRepo.saveAndFlush(myModel);
} catch ( Exception e) {
e.printStackTrace();
}
return mm;
}
UPDATE:
I finally realized that my problem is due to a database trigger that auto-generates primary key against a complex business rule. Also, I assume I might need to use a custom save method rather than the default repo.saveAndFlush? I would be grateful for any ideas given new information. Thanks!
I reproduced the exact same code in a test project with Postgres and it worked well for me. You are absolutely correct that the values of the model class are not populated. You must share your controller also. It may really help me to help you if I can get a look where your service is being called from. Only that will help me to deduce why your model values are being passed as null in the service call.
I have the following class:
public class House {
#Id
#GeneratedValue
private long id;
private String title;
private String description;
private String city;
private double price;
private String phoneNumber;
}
I need to make a #GetMapping, where I have to get every attribute of a house except it's city.
I tried this:
This is in my repository:
public House findByIdButCity(long id) {
return em.createQuery("SELECT h.title, h.description, h.price FROM House h WHERE h.id = :id", House.class).setParameter("id", id).getSingleResult();
}
And this is in my controller:
#GetMapping("{id}")
public ResponseEntity<House> getAttributesButCityById(#PathVariable long id) {
House house = houseRepository.findByIdButCity(id);
if (house == null)
return ResponseEntity.notFound().build();
else
return ResponseEntity.ok(property);
}
Instead of filter the fields in the select, get all the information of a house and then map it to an object in the controller with only the information that you want to return, this way you also will decouple your database model from your API:
public House findByIdButCity(long id) {
return em.createQuery("SELECT h FROM House h WHERE h.id = :id", House.class).setParameter("id", id).getSingleResult();
}
public class HoouseDto {
private String title;
private String description;
private double price;
}
#GetMapping("{id}")
public ResponseEntity<HouseDto> getAttributesButCityById(#PathVariable long id) {
House house = houseRepository.findByIdButCity(id);
if (house == null)
return ResponseEntity.notFound().build();
else {
HouseDto houseDto = mapper.toDto(house)
return ResponseEntity.ok(houseDto);
}
}
}
You can use mapstruct to make the mapper or you can create a class with a static method to do it
Mapper example
public class HouseMapper {
public static HouseDto toDto(House house) {
HouseDto houseDto = new HouseDto();
houseDto.setTitle(house.getTitle());
houseDto.setDescription(house.getDescription());
houseDto.setPrice(house.getDescription());
return houseDto;
}
You can do more easily if you include the mapstruct with spring because you only have to define an interface and it will create the implementation mapping the attributes that with same names.
Here is an example:
https://www.baeldung.com/mapstruct
try changing your query to
SELECT h FROM House h WHERE h.id = :id
I have to create an application with Jhipster but i never use it before.
When a user send a GET request to the address http://localhost:8080/api/newmesure/{mac-address}/{value}
I want to insert a new mesure in my database.
First i created 3 entity "Plantes", "Capteurs" and "Mesures" with this format :
Image here : https://i.stack.imgur.com/zJqia.png (I'm not allowed to post)
I activated the JPA Filtering to create a #Query to insert data in my database but i read that was not possible.
In /src/main/java/com/mycompany/myapp/web/rest/MesuresRessources.java :
/**
* REST controller for managing {#link com.mycompany.myapp.domain.Mesures}.
*/
#RestController
#RequestMapping("/api")
public class MesuresResource {
private final Logger log = LoggerFactory.getLogger(MesuresResource.class);
private static final String ENTITY_NAME = "mesures";
#Value("${jhipster.clientApp.name}")
private String applicationName;
private final MesuresService mesuresService;
private final MesuresQueryService mesuresQueryService;
public MesuresResource(MesuresService mesuresService, MesuresQueryService mesuresQueryService) {
this.mesuresService = mesuresService;
this.mesuresQueryService = mesuresQueryService;
}
#GetMapping("/newMesure/{mac}/{value}")
public String newMesure(#PathVariable String mac,#PathVariable int value) {
log.debug("Adresse MAC : "+mac);
log.debug("Valeur : "+value);
#Query("SELECT valeur FROM Mesures WHERE id = 1") //not working
Mesures getValeur(); //not working
return "Mesure ajoutée";
}
}
In /src/main/java/com/mycompany/myapp/domain/Mesures.java :
/**
* A Mesures.
*/
#Entity
#Table(name = "mesures")
public class Mesures implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "valeur")
private Integer valeur;
#ManyToOne(optional = false)
#NotNull
#JsonIgnoreProperties("macs")
private Capteurs mac;
// jhipster-needle-entity-add-field - JHipster will add fields here, do not remove
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Integer getValeur() {
return valeur;
}
public Mesures valeur(Integer valeur) {
this.valeur = valeur;
return this;
}
public void setValeur(Integer valeur) {
this.valeur = valeur;
}
public Capteurs getMac() {
return mac;
}
public Mesures mac(Capteurs capteurs) {
this.mac = capteurs;
return this;
}
public void setMac(Capteurs capteurs) {
this.mac = capteurs;
}
// jhipster-needle-entity-add-getters-setters - JHipster will add getters and setters here, do not remove
#Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof Mesures)) {
return false;
}
return id != null && id.equals(((Mesures) o).id);
}
#Override
public int hashCode() {
return 31;
}
#Override
public String toString() {
return "Mesures{" +
"id=" + getId() +
", valeur=" + getValeur() +
"}";
}
}
Louan
Learning java with JHipster is probably not a wise idea, it uses a very rich technology stack which might lose you unless you invest enough time to learn the basics.
There are many things wrong in your code and approach:
You can't use #Query annotation inside the body of method a of your REST controller, it must be used in your #Repository interface, this code can't compile. See https://www.baeldung.com/spring-data-jpa-query for a quick introduction
JPA filtering is not related to inserting into database
In HTTP/REST, GET method is supposed to be idempotent. For making changes in your database you should use POST or PUT methods. See What is idempotency in HTTP methods?
Your entity naming convention is not consistent: use singular for entity classes because each entity object represents one single instance of Mesure. Here you have Plantes (plural), Capteur (singular) and Mesures (plural). For table names, JHipster uses singular but plural is quite common too because a table holds many rows. Of course, this is just a convention and you or your team may decide to apply another (like a prefix for table names) but the key point is to be consistent.
We have two tables that have a one to many relationship. When we insert multiple records into the child table across multiple threads (more specifically across multiple REST web requests) we are running into lost update issues due to a race condition.
What we need to be able to do is have JPA recognize that the entity has been updated elsewhere prior to inserting the child record. I've tried using the #Version annotation approach but that doesn't seem to do the trick as the update/insert (I guess...) is happening on another table. I tried adding a version timestamp column on the parent table that is updated on every update but that didn't seem to do the trick either.
I think what I actually need to do is get a reference to the EntityManager directly so that I can issue a lock() command on the record prior to calling save(). I'm just too new to Spring to know if
A) that is indeed the correct approach,
B) if there is a better/easier way to do what we are trying to accomplish, and
C) how to actually do that.
Also, I am aware of the #OneToMany annotation but that didn't seem to do anything.
I've truncated the code below for brevity and I also created a trimmed down version of the code that demonstrates the problem and will hopefully make it easier to see what I am trying to do. In the test if you change the thread pool number to 1 you can see the test pass.
Engagement class:
#Entity
public class Engagement implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Long id;
#ElementCollection(fetch = EAGER)
private List<String> assignedUsers;
#Version
private Long version;
private LocalDateTime updatedOn;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Long getVersion(){return version;}
public void setVersion(Long version){this.version = version;}
public LocalDateTime getUpdatedOn(){
return updatedOn;
}
public void setUpdatedOn(LocalDateTime updatedOn) {
this.updatedOn = updatedOn;
}
public List<String> getAssignedUsers() {
return assignedUsers;
}
public void setAssignedUsers(List<String> assignedUsers) {
this.assignedUsers = assignedUsers;
}
public Engagement() {
}
}
User class:
public final class User {
private final String name;
private final String email;
private final String userId;
private final List<Engagement> engagements;
#ConstructorProperties({"roles", "name", "email", "userId", "engagements"})
User(String name, String email, String userId, List<Engagement> engagements) {
this.name = name;
this.email = email;
this.userId = userId;
this.engagements = engagements;
}
public static User.UserBuilder builder() {
return new User.UserBuilder();
}
public String getName() {
return this.name;
}
public String getEmail() {
return this.email;
}
public String getUserId() {
return this.userId;
}
public List<Engagement> getEngagements() {
return this.engagements;
}
public static final class UserBuilder {
private String name;
private String email;
private String userId;
private List<Engagement> engagements;
UserBuilder() {
}
public User.UserBuilder name(String name) {
this.name = name;
return this;
}
public User.UserBuilder email(String email) {
this.email = email;
return this;
}
public User.UserBuilder userId(String userId) {
this.userId = userId;
return this;
}
public User.UserBuilder engagements(List<Engagement> engagements) {
this.engagements = engagements;
return this;
}
public User build() {
return new User(this.name, this.email, this.userId, this.engagements);
}
public String toString() {
return "User.UserBuilder(name=" + this.name + ", email=" + this.email + ", userId=" + this.userId + ", engagements=" + this.engagements + ")";
}
}
}
Thread test:
#RunWith(SpringJUnit4ClassRunner.class)
#SpringBootTest
public class EngagementTest {
#Mock
UsersAuthService usersService;
#Autowired
EngagementsRepository engagementsRepository;
UsersAuthService authService;
#Before
public void init() {
MockitoAnnotations.initMocks(this);
authService = new UsersAuthServiceImpl(usersService, engagementsRepository);
}
#Test
public void addingMultipleUsersAtOnceSucceeds() throws InterruptedException {
Long engagementId = 1L;
String userId1 = "user1";
String userId2 = "user2";
String userId3 = "user3";
String userId4 = "user4";
String userId5 = "user5";
String auth = "asdf";
User adminUser = User.builder()
.userId("adminUser")
.email("user#user.com")
.name("Admin User")
.build();
Engagement engagement = new Engagement();
engagement.setAssignedUsers(new ArrayList<>());
engagement.getAssignedUsers().add(adminUser.getUserId());
engagementsRepository.save(engagement);
ExecutorService executorService = Executors.newFixedThreadPool(5);//change this to 1 to see the test pass
List<Callable<Engagement>> callableList = Arrays.asList(
addUserThread(engagementId, userId1, auth, adminUser),
addUserThread(engagementId, userId2, auth, adminUser),
addUserThread(engagementId, userId3, auth, adminUser),
addUserThread(engagementId, userId4, auth, adminUser),
addUserThread(engagementId, userId5, auth, adminUser));
executorService.invokeAll(callableList);
Engagement after = engagementsRepository.findById(engagementId);
assertEquals(6, after.getAssignedUsers().size());
}
private Callable<Engagement> addUserThread(Long engagementId, String userId1, String auth, User adminUser) {
return () -> authService.addUserTo(engagementId, userId1, auth, adminUser);
}
}
What's happening here is that you submit the callbacks for execution but never actually wait for their completion before checking the result. You need to use the List<Future<Engagement>> to actually wait for the results to complete before proceeding.
Something like this would do the trick:
executorService.invokeAll(callableList).forEach(it -> {
try {
it.get(500, TimeUnit.MILLISECONDS);
} catch (InterruptedException | ExecutionException | TimeoutException e) {
e.printStackTrace();
}
});
Note that this is not a proper way to deal with the exception case but it causes the code to wait for completion. If you have that in place you see the threads properly rejecting some of the updates with an ObjectOptimisticLockingFailureException:
java.util.concurrent.ExecutionException: org.springframework.orm.ObjectOptimisticLockingFailureException: Object of class [com.example.racecondition.engagement.Engagement] with identifier [1]: optimistic locking failed; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [com.example.racecondition.engagement.Engagement#1]
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:206)
at com.example.racecondition.EngagementTest.lambda$0(EngagementTest.java:68)
at java.util.ArrayList.forEach(ArrayList.java:1257)
at com.example.racecondition.EngagementTest.addingMultipleUsersAtOnceSucceeds(EngagementTest.java:66)
What's weird about the test case beyond that is that UsersAuthServiceImpl carries an #Transactional but the test case manually instantiates that class, so that there's no transactional proxy in place already. This causes the calls to findById(…) and save(…) from within addToUser(…) to run in two transactions. Tweaking that doesn't change the output though.
I think what I actually need to do is get a reference to the EntityManager directly so that I can issue a lock() command on the record prior to calling save(). I'm just too new to Spring to know if
A) that is indeed the correct approach,
If I understand you correctly you want to basically force a version increment on an entity so that if multiple threads do that one fails.
You can indeed achieve that by locking the entity in question using LockModeType.PESSIMISTIC_FORCE_INCREMENT or LockModeType.OPTIMISTIC_FORCE_INCREMENT.
B) if there is a better/easier way to do what we are trying to accomplish, and
C) how to actually do that.
With Spring Data probably the best way to do that is using the #Lock annotation on the method you use to load the entity.
I have this enum :
public enum DocumentTypes {
PDF("PDF Document"), JPG("Image files (JPG)"), DOC("Microsoft Word documents");
private final String displayName;
DocumentTypes(final String display) {
this.displayName = display;
}
#Override
public String toString() {
return this.displayName;
}
}
And a model like this :
#Entity
#Table(name = "documents")
public class Document extends Model {
#Id
public Long id;
#Constraints.Required
#Formats.NonEmpty
#Enumerated(EnumType.STRING)
#Column(length=20, nullable=false)
public DocumentTypes type;
#Constraints.Required
#Formats.NonEmpty
#Column(nullable=false)
public String document;
}
I match the enum using this in my controller :
DynamicForm form = form().bindFromRequest();
// ...
Document doc = new Document();
doc.type = DocumentTypes.valueOf(form.field("type").value());
doc.save();
The problem is that in database, it's stored as "Microsoft Word documents", but I would prefer to store it as DOC.
How can I do that?
You can define it very fine granular with the Anotation EnumMapping or EnumValue. This works with the old version org.avaje.ebean.
It seems that there was a complete rewrite of the code. In the actual version there is a different approach.