Spring Data Rest & Lombok - Exception while adding adding relation - spring

In my project I have 2 entities. Survey and entries to survey. They are in relation one to many (thare can be many entries to one survey).
#NoArgsConstructor
#AllArgsConstructor
#Getter
#Setter
#Entity
#Table(name = "survey_entries")
#TypeDef(name = "SurveyEntry", typeClass = SurveyEntry.class)
public class SurveyEntryEntity extends AbstractEntity {
#ManyToOne
#JoinColumn(name = "survey_id")
private SurveyEntity survey;
#NonNull
#Type(type = "SurveyEntry")
#Column(name = "responses")
// JSON db column type mapped to custom type
private SurveyEntry responses;
}
#NoArgsConstructor
#AllArgsConstructor
#Getter
#Setter
#Entity
#Table(name = "surveys")
#TypeDef(name = "Survey", typeClass = Survey.class)
public class SurveyEntity extends AbstractEntity {
#NonNull
#Type(type = "Survey")
#Column(name = "template")
// JSON db column type mapped to custom type
private Survey survey;
#OneToMany(mappedBy = "survey")
private List<SurveyEntryEntity> entries;
}
I have also created 2 rest repositories using Spring Data Rest:
#RepositoryRestResource(collectionResourceRel = "survey_entries", path = "survey-entries")
public interface SurveyEntryRepository extends PagingAndSortingRepository<SurveyEntryEntity, Long> {
}
#RepositoryRestResource(collectionResourceRel = "surveys", path = "surveys")
public interface SurveyRepository extends PagingAndSortingRepository<SurveyEntity,Long> {
}
I have successfully added survey by rest POST request and I can access it entries (currently empty) by sending GET to /api/surveys/1/entries.Now I want to add entry to exisiting survey. And while I can add it by sending POST (content below) to /api/survey-entries I have troubles adding it directly as a reference to survey. I'm using POST method with the same content and url /api/surveys/1/entries. What is interesting, I'm getting NullPointerException in logs and entry is not inserted but audit modify timestamp in survey is changed. What am I doing wrong? Did I miss same configuration? Or should I use different content?
Content of POST with entry:
{
"responses": {
"question1": "response1",
"question2": "response2",
"question3": "response3"
}
}
Content of POST with survey:
{
"survey": {
//survey structure
}
}
Exception:
08:41:14.730 [http-nio-8080-exec-3] DEBUG org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod - Failed to resolve argument 1 of type 'org.springframework.data.rest.webmvc.PersistentEntityResource'
org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: No content to map due to end-of-input; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input
Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input
#EDIT
I have tried adding entry by POST to /api/survey-entries with 'application/hal+json' Content-Type header and content as below, but now I'm getting other exception:
Content:
{
"survey" : "http://localhost:8080/api/surveys/1",
"responses": {
"question1": "response1",
"question2": "response2",
"question3": "response3"
}
}
Exception:
Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.domain.SurveyEntity` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('http://localhost:8080/api/surveys/1')
at [Source: (org.apache.catalina.connector.CoyoteInputStream); line: 1, column: 41] (through reference chain: com.domain.SurveyEntryEntity["survey"])
#Edit 2
Added Lombok annotations present on Entity classess

Unfortunatelly problem lied in Lombok annotations which weren't included in sample code. I added them now so any one can see where the problem lies.
I managed to solve it by downgrading Lombok to version (1.16.14) and changing annotation #AllArgsConstructor to #AllArgsConstructor(suppressConstructorProperties = true). It's immposible to achieve in later Lombok versions as this property is currently removed.
I have found solution on Spring Data Rest JIRA. There is already issue DATAREST-884 mentioning problem and presenting solution/workaround.
Sorry for wasted time while it was impossible to see solution without all the code.

Related

Spring WebClient Post body not getting passed

I am trying to use WebClient to Post a loan object to another microservice which saves this object in a DB. So theoretically the body (JSON loan object) should just be passed on to the API of the DB service. Somehow, I can't figure out how to accomplish this.
This is the API that accepts the JSON loan object:
Mapping: localhost:8081/loans
#PostMapping
public <T extends Loan> void addLoan(#Valid #NonNull #RequestBody T loan) {
loanService.createLoan(loan);
}
It then calls the loanService which should pass on the loan object to the DB-service API
public <T extends Loan> T createLoan(T loan) {
ParameterizedTypeReference<T> typeReference = new ParameterizedTypeReference<T>(){};
T a = client.post().uri("/loans").body(BodyInserters.fromValue(loan)).retrieve().bodyToMono(typeReference).block();
return a;
}
This is the API of that DB service:
Mapping: localhost:8080/api/v1/loans
#PostMapping
#ResponseBody
public <T extends Loan> T createLoan(#RequestBody T loan) {
return loanService.createLoan(loan);
}
And here is its service:
public <T extends Loan> T createLoan(T Loan) {
return (T) loanRepository.save(Loan);
}
If I just pass a loan object directly to the DB service API, everything works fine. But if I pass it to the other API, I get the following error:
"status": 500,
"error": "Internal Server Error",
"trace": "org.springframework.web.reactive.function.client.WebClientResponseException$InternalServerError: 500 Internal Server Error from POST http://localhost:8080/api/v1/loans/\n\tat org.springframework.web.reactive.function.client.WebClientResponseException.create(WebClientResponseException.java:201)\n\tSuppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: \nError has been observed at the following site(s):\n\t|_ checkpoint ⇢ 500 from POST http://localhost:8080/api/v1/loans/ [DefaultWebClient]\nStack trace:\n\t\tat org.springframework.web.reactive.function.client.WebClientResponseException.create(WebClientResponseException.java:201)\n\t\tat org.springframework.web.reactive.function.client.DefaultClientResponse.lambda$createException$1(DefaultClientResponse.java:216)\n\t\tat reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:106)\n\t\tat reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79)\n\t\tat reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onNext(FluxDefaultIfEmpty.java:99)\n\t\tat reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:127)\n\t\tat reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onNext(FluxContextWrite.java:107)\n\t\tat reactor.core.publisher.FluxMapFuseable$MapFuseableConditionalSubscriber.onNext(FluxMapFuseable.java:295)\n\t\tat reactor.core.publisher.FluxFilterFuseable$FilterFuseableConditionalSubscriber.onNext(FluxFilterFuseable.java:337)\n\t\tat reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1784)\n\t\tat reactor.core.publisher.MonoCollect$CollectSubscriber.onComplete(MonoCollect.java:159)\n\t\tat reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:142)\n\t\tat reactor.core.publisher.FluxPeek$PeekSubscriber.onComplete(FluxPeek.java:259)\n\t\tat reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:142)\n\t\tat reactor.netty.channel.FluxReceive.onInboundComplete(FluxReceive.java:383)\n\t\tat reactor.netty.channel.ChannelOperations.onInboundComplete(ChannelOperations.java:396)\n\t\tat reactor.netty.channel.ChannelOperations.terminate(ChannelOperations.java:452)\n\t\tat reactor.netty.http.client.HttpClientOperations.onInboundNext(HttpClientOperations.java:664)\n\t\tat reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:94)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)\n\t\tat io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)\n\t\tat io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436)\n\t\tat io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324)\n\t\tat io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296)\n\t\tat io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)\n\t\tat io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)\n\t\tat io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)\n\t\tat io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)\n\t\tat io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:795)\n\t\tat io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:480)\n\t\tat io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:378)\n\t\tat io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)\n\t\tat io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)\n\t\tat io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)\n\t\tat java.base/java.lang.Thread.run(Thread.java:832)\n\tSuppressed: java.lang.Exception: #block terminated with an error\n\t\tat reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:99)\n\t\tat reactor.core.publisher.Mono.block(Mono.java:1679)\n\t\tat de.rwth.swc.lab.ws2021.daifu.businesslogic.services.LoanService.createLoan(LoanService.java:39)\n\t\tat de.rwth.swc.lab.ws2021.daifu.businesslogic.api.LoanController.addLoan(LoanController.java:28)\n\t\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\t\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)\n\t\tat java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\t\tat java.base/java.lang.reflect.Method.invoke(Method.java:564)\n\t\tat org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197)\n\t\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141)\n\t\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)\n\t\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:893)\n\t\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:807)\n\t\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\n\t\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1061)\n\t\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:961)\n\t\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)\n\t\tat org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)\n\t\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:652)\n\t\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)\n\t\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:733)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\t\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\t\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)\n\t\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\t\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)\n\t\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\t\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)\n\t\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\t\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\t\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)\n\t\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)\n\t\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)\n\t\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)\n\t\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n\t\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)\n\t\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)\n\t\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)\n\t\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\n\t\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)\n\t\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)\n\t\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\n\t\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)\n\t\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)\n\t\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n\t\tat java.base/java.lang.Thread.run(Thread.java:832)\n",
"message": "500 Internal Server Error from POST http://localhost:8080/api/v1/loans/",
"path": "/loans/"
This is the server-side error:
Servlet.service() for servlet [dispatcherServlet] in context with path [/api/v1] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: not-null property references a null or transient value : de.rwth.swc.lab.ws2021.daifu.dataservice.data.models.loans.PrivateLoan.customer; nested exception is org.hibernate.PropertyValueException: not-null property references a null or transient value : de.rwth.swc.lab.ws2021.daifu.dataservice.data.models.loans.PrivateLoan.customer] with root cause org.hibernate.PropertyValueException: not-null property references a null or transient value : de.rwth.swc.lab.ws2021.daifu.dataservice.data.models.loans.PrivateLoan.customer
And finally, this is the POST-body:
{
"amount": 10000.00,
"balance": -2000.00,
"customer": {"id": 1},
"interest": 0.06,
"status": "TIMELY",
"reason": "Some reaseon",
"type": "privateLoan"
}
The error says the "not-null property references a null or transient value" but the exact same request works for a direct POST-request to the 2nd API which doesn't make sense to me.
Here is the loan class:
#Entity
#Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
#Getter
#Setter
#NoArgsConstructor
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
#JsonSubTypes({
#JsonSubTypes.Type(value = CarLoan.class, name = "carLoan"),
#JsonSubTypes.Type(value = ConstructionLoan.class, name = "constructionLoan"),
#JsonSubTypes.Type(value = Mortgage.class, name = "mortgage"),
#JsonSubTypes.Type(value = PrivateLoan.class, name = "privateLoan"),
#JsonSubTypes.Type(value = PropertyLoan.class, name = "propertyLoan")
})
#ApiModel(
discriminator = "type",
subTypes = {CarLoan.class, ConstructionLoan.class, Mortgage.class, PrivateLoan.class, PropertyLoan.class}
)
public abstract class Loan {
#Id
#GeneratedValue(strategy = GenerationType.TABLE)
#Column(name = "id")
#ApiModelProperty(required = false, hidden = true)
protected Integer id;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "customer_id", nullable = false)
#JsonBackReference(value = "customer-loans")
protected Customer customer;
#OneToMany(mappedBy = "loan", cascade = CascadeType.ALL)
#JsonManagedReference(value = "loan-loanRates")
private Set<LoanRate> loanRates;
#NonNull
protected Double amount;
#NonNull
protected Double interest;
#NonNull
protected Double balance;
#NonNull
protected LoanStatus status;
public enum LoanStatus {
TIMELY("timely"),
GRACE_PERIOD("grace period"),
DEFAULT("default"),
DEFICIT("deficit"),
IRRECOVERABLE_DEBT("irrecoverable debt"),
CLOSED("closed");
#Getter
private String stringRepresentation;
private LoanStatus(String s) {
this.stringRepresentation = s;
}
}
public <T extends Loan> boolean isOfSameInstance(T otherLoan) {
return (this.getClass().equals(otherLoan.getClass()));
}
}
Let me know if I should post anything else.
Thanks in advance.
The problem is due to the models being used in the projects. As your are reusing the model classes of the one webservice which offers the CRUD api for the backend, you are also reusing the jackson's #JsonManagedReference and #JsonBackReference. This leads to null values for the models being defined as the back reference, such as the customer in you loan class. Jackson does not serialize such tagged objects to JSON in order to not run into a stackoverflow due to infinite recursion. Thus, when you serialize a loan model in your service and send the request to the other service, jackson nulls the back reference, e.g. customer in the loan model and the 2nd webservice therefore receives an invalid loan model, since a loan model is required to have a customer not to be null.
I suggest to either remove the jackson annotations from the models in the service you develop, which would required copy pasted model classes (on the one side the classes using the required jackson annotations in the web service, and on the other side the classes not using these in the other web service). However, this solution has the typical disadvantages of duplicated code. The more elegant but more complicated solution will be to implement a custom jackson serializer and deserializer by specializing jackson's StdSerializer<Loan> and StdDeserializer<Loan>. These custom serializers and deserializers should override its serialize(T value, JsonGenerator gen, SerializerProvider provider) respectively its deserialize(JsonParser, DeserializationContext) method such that the #JsonManagedReference and #JsonBackReference, as well as, if being used, #JsonIgnore annotations in the model are being ignored.
It might be sufficient to just implement a custom serializer. However, I guess that you will also run into problems when receiving a response from the other web service when not using a custom deserializer.
This error may happen if the customer object in the loan you are trying to save is null or not yet added to the database (even though it is set in loan). You should check before saving the Loan in the DB if customer is null or not. If not, and if it is a customer not yet in the database, you should consider adding it first or specify CascadeType.PERSIST in the relation type annotation. In any case, it would be better if you post the entire model that both services are using.

CRUDRepository findBy foreign key id causing exception: Unable to locate Attribute with the the given name [classroomId] on this ManagedType

I am getting an exception when creating a custom findBy method by a foreign key.
Entity class:
#Entity
#Getter
#Setter
public class Thread {
private #Id #GeneratedValue Long id;
private String subject;
#ManyToOne(fetch = FetchType.LAZY)
#JsonIgnore
private Classroom classroom;
protected Thread() {}
public Long getClassroomId() {
return this.classroom.getId();
}
}
ThreadRepository class:
public interface ThreadRepository extends CrudRepository<Thread, Long> {
List<Thread> findByClassroomId(Long id);
}
I get the exception:
java.lang.IllegalArgumentException: Unable to locate Attribute with the the given name [classroomId] on this ManagedType [com.futurerprood.unicycleservice.entity.threads.Thread]
But the exception goes away if I remove the getClassroomId() in the Thread class. I have this function so that the json serialization will pick up only the classroom id instead of the whole classroom object in an endpoint response.
Why is this function causing the foreign key unable to be found?
You can do one of the following:
Provide the query to the repository method
#Query("select e from Thread t join t.classroom c where c.id = :id")
List<Thread> findByClassroomId(Long id);
Rename the repository method
List<Event> findByClassroom_Id(Long id);
Update
Explanation as to why these two are working
First, have a look at https://docs.spring.io/spring-data/jpa/docs/1.4.3.RELEASE/reference/htmlsingle/#d0e391 and understand how property traversal based on method name happens in Spring data JPA in order to generate the query and how ambiguity resolution is recommended.
In the first one, we tell spring data, it does not need to do property traversal to generate the JPA query as we are giving the query so it does not get any ambiguity.
In the second, as recommended in the reference, we are resolving the ambiguity for Spring Data JPA by telling it to go to Classroom object first. But as #crizzis pointed out under the question comment, Spring data should have treated it as ambiguity in the first place

"Parameter specified as non-null is null" is thrown when trying to reference one JDL entity from another entity in JHipster Kotlin

I'm trying to build a website in JDL Kotlin, but am having a problem with the JDL generated entities and edit forms. I have a JDL entity called Provider, an entity called Plan that needs to reference which provider it belongs to, and a third entity called PerDayPricing that references both Provider and Plan, all as per the following JDL configuration:
entity Provider {
// [...]
}
entity Plan {
// [...]
}
entity PerDayPricing {
// [...]
}
relationship OneToMany {
Provider to Plan
}
relationship OneToMany {
Provider to PerDayPricing
Plan to PerDayPricing
}
service all with serviceImpl
However, when I try to create or set the Provider field on a Plan item, it spits out the following error:
WARN [PID] --- [ XNIO-1 task-10] .m.m.a.ExceptionHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageConversionException: JSON conversion problem: Parameter specified as non-null is null: method com.example.project.domain.Plan.setPerDayPricings, parameter <set-?>; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Parameter specified as non-null is null: method com.example.project.domain.Plan.setPerDayPricings, parameter <set-?> (through reference chain: com.example.project.domain.Plan["perDayPricings"])]
PerDayPricing is referenced here even though I didn't change any of its items. When I do try to set the Provider field on a PerDayPricing item, it gives the following error:
WARN [PID] --- [ XNIO-1 task-32] .m.m.a.ExceptionHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageConversionException: JSON conversion problem: Parameter specified as non-null is null: method com.example.project.domain.Provider.setPlans, parameter <set-?>; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Parameter specified as non-null is null: method com.example.project.domain.Provider.setPlans, parameter <set-?> (through reference chain: com.example.project.domain.PerDayPricing["provider"]->com.example.project.domain.Provider["plans"])]
I actually have no idea what's going on here as I don't have a lot of experience with JHipster. I simply imported the JDL source file and let JHipster create files based on its configuration, without changing any of them, and this is already happening. References to the method names setPlans and setPerDayPricings don't even exist in the codebase, so I'm assuming they are being generated by Kotlin in the background?
Does anyone know what's going on and how I can fix it?
Edit: The following are the signatures of the entity classes (regular fields were removed for brevity):
// src/main/kotlin/domain/Provider.kt
#Entity
#Table(name = "plan")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
data class Plan(
// [...]
#OneToMany(mappedBy = "plan")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
var perDayPricings: MutableSet<PerDayPricing> = mutableSetOf(),
#OneToMany(mappedBy = "plan")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
var fixedDurationPricings: MutableSet<FixedDurationPricing> = mutableSetOf(),
#ManyToOne #JsonIgnoreProperties("plans")
var provider: Provider? = null
// jhipster-needle-entity-add-field - JHipster will add fields here, do not remove
) : Serializable
// src/main/kotlin/domain/Plan.kt
#Entity
#Table(name = "provider")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
data class Provider(
// [...]
#OneToMany(mappedBy = "provider")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
var plans: MutableSet<Plan> = mutableSetOf(),
#OneToMany(mappedBy = "provider")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
var perDayPricings: MutableSet<PerDayPricing> = mutableSetOf(),
#OneToMany(mappedBy = "provider")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
var fixedDurationPricings: MutableSet<FixedDurationPricing> = mutableSetOf()
// jhipster-needle-entity-add-field - JHipster will add fields here, do not remove
) : Serializable
// src/main/kotlin/domain/PerDayPricing.kt
/**
* A PerDayPricing.
*/
#Entity
#Table(name = "per_day_pricing")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
data class PerDayPricing(
// [...]
#ManyToOne #JsonIgnoreProperties("perDayPricings")
var provider: Provider? = null,
#ManyToOne #JsonIgnoreProperties("perDayPricings")
var plan: Plan? = null
// jhipster-needle-entity-add-field - JHipster will add fields here, do not remove
) : Serializable
If it generates data classes, then compiler will generate you the setters and getters. I suppose, when you want to set the entity to one another, you did not provide those fields from the exception. Kotlin not support null values by default. So either you have to provide those fields or mark the type as nullable with ? (question mark) at the and of the type. For example
var perDayPricings:String?
You should update the question with the given code, so we can see what is the problem.

Spring Data JPA and Generics

I have an entity that looks like this
#Entity(name = "encounter_pdf_export")
public class EncounterPDFExport<T extends Encounter> implements Serializable {
public static final long serialVersionUID = 1L;
#Id
#GeneratedValue
private Long pdfExportId;
#Any(metaColumn = #Column(name = "encounter_type"))
#Cascade(CascadeType.ALL)
#AnyMetaDef(
idType = "long",
metaType = "string",
metaValues = {
#MetaValue(value = "FooEncounter", targetEntity = FooEncounter.class)
})
#JoinColumn(name = "encounter_id")
private T encounter;
The abstract type that I'm extending is:
public abstract class Encounter {
public abstract Long getEncounterId();
}
Here is my Spring Data Repository
#Repository
public interface EncounterPDFExportRepository extends PagingAndSortingRepository<EncounterPDFExport, Long> {
EncounterPDFExport findOneByEncounter_encounterId(#Param("encounterId") Long encounterId);
}
I am getting a stack trace when starting up the application related to to the findOneByEncounter_encounterId method:
Caused by: java.lang.IllegalArgumentException: Unable to locate Attribute with the the given name [encounter] on this ManagedType [com.iimassociates.distiller.domain.EncounterPDFExport]
at org.hibernate.jpa.internal.metamodel.AbstractManagedType.checkNotNull(AbstractManagedType.java:144)
at org.hibernate.jpa.internal.metamodel.AbstractManagedType.getAttribute(AbstractManagedType.java:130)
at org.springframework.data.jpa.repository.query.QueryUtils.toExpressionRecursively(QueryUtils.java:468)
at org.springframework.data.jpa.repository.query.JpaQueryCreator$PredicateBuilder.getTypedPath(JpaQueryCreator.java:300)
at org.springframework.data.jpa.repository.query.JpaQueryCreator$PredicateBuilder.build(JpaQueryCreator.java:243)
at org.springframework.data.jpa.repository.query.JpaQueryCreator.toPredicate(JpaQueryCreator.java:148)
at org.springframework.data.jpa.repository.query.JpaQueryCreator.create(JpaQueryCreator.java:88)
at org.springframework.data.jpa.repository.query.JpaQueryCreator.create(JpaQueryCreator.java:46)
at org.springframework.data.repository.query.parser.AbstractQueryCreator.createCriteria(AbstractQueryCreator.java:109)
at org.springframework.data.repository.query.parser.AbstractQueryCreator.createQuery(AbstractQueryCreator.java:88)
at org.springframework.data.repository.query.parser.AbstractQueryCreator.createQuery(AbstractQueryCreator.java:73)
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery$QueryPreparer.<init>(PartTreeJpaQuery.java:116)
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery$CountQueryPreparer.<init>(PartTreeJpaQuery.java:237)
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery.<init>(PartTreeJpaQuery.java:65)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:100)
I am assuming that either Spring Data JPA doesn't support abstracted/generic fields? If that's the case, would creating a #Query be a sufficient workaround?
Not sure if this will be helpful to anyone, but I did get this working.
Removed the abstract class and made it an interface with a single public getEncounterId() method
Modified FooEncounter to implement the above interface
Removed generics from the EncounterPDFExport class
Modified the encounter field to utilize the above interface rather than a generic
Apparently, I'm hitting some Hibernate bug/limitation when accessing fields within FooEncounter. Accessing Encounter within EncounterPDFExport works OK, though. I modified my Spring Data JPA Repository to look like the following (note the modification from finding by encounter.encounterId vs. just encounter):
#Repository
public interface EncounterPDFExportRepository extends PagingAndSortingRepository<EncounterPDFExport, Long> {
EncounterPDFExport findOneByEncounter(#Param("encounter") Encounter encounter);
}
The Hibernate bug in question seems to be related to https://jira.spring.io/browse/DATAJPA-836.

Spring Data JPA with MVC repository

I am building a Spring repository for some JPA-annotated entities. I have created a repository:
public interface AppRepository extends PagingAndSortingRepository<App, String>
{
}
The App class looks as follows:
#Entity
public class App implements Serializable
{
#Id
private String appId;
#OneToMany(mappedBy = "app")
private List<AgentUser> agentusers;
#OneToMany(mappedBy = "app")
private List<AppFacet> appfacets;
// getters and setters go here
}
where the AgentUser and the AppFacet hold a reference property called app towards an App object. In the AgentUser class, I have changed the RestResource rel:
#Entity
public class AgentUser
{
...
#ManyToOne
#JoinColumn(name = "AppId")
#RestResource(rel = "agentUserToApp", exported = false)
private App app;
// other properties go here
}
I am getting the following error message while querying the /apps path:
org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: Infinite recursion (StackOverflowError) (through reference chain: org.springframework.hateoas.PagedResources["_embedded"]);
Do you know what could be causing it? Please note that I only have one App object in a database, for testing purposes and no other kind of object.
Update
The trace is:
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:677)
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:129)
com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2240)
org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:231)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:208)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:161)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:101)
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:167)
And after that, a lot of:
org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations(BasicPersistentEntity.java:352)
org.springframework.data.rest.webmvc.mapping.LinkCollectingAssociationHandler.doWithAssociation(LinkCollectingAssociationHandler.java:101)
The problem resides in that, whenever you have links to some entities, you must implement a repository for that entity too, in order to generate the proper links.

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