JPA Entity Graph using Builder pattern

Question

I have a car table like this:

+----+------+--------------+-----------+----------+------+
| Id | Name | Description |   Make    |  Model   | Year |
+----+------+--------------+-----------+----------+------+
|  1 | A    | something1   | Ford      | Explorer | 2010 |
|  2 | B    | something2   | Nissan    | Ultima   | 2005 |
|  3 | C    | something3   | Chevrolet | Malibu   | 2012 |
+----+------+--------------+-----------+----------+------+

And a Car entity that looks like this:

@Entity
@Table(schema = "dbo", name = "Car")
public class CarEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @Column(name = "Name")
    private String name;

    @Column(name = "Description")
    private String description;

    @Column(name = "Make")
    private String make;

    @Column(name = "Model")
    private String model;

    @Column(name = "Year")
    private int year;

    //Getters and Setters for all attributes
}

I have a repository layer like this:

public interface CarRepository {
    CarRepository getCar();

    CarRepository withName();

    CarRepository withDescription();

    CarRepository withMake();

    CarRepository withModel();

    CarRepository withYear();

    List<Car> build(int carId);
}

My Repository implementation looks like this:

@Repository
public class JpaCarRepository implements CarRepository {
    private static EntityGraph<CarEntity> eg;

    @Override
    public CarRepository getCar() {
        eg = this.em.createEntityGraph(CarEntity.class);
        eg.addAttributeNodes("id");
        return this;
    }

    @Override
    public CarRepository withName() {
        eg.addAttributeNodes("name");
        return this;
    }

    @Override
    public CarRepository withDescription() {
        eg.addAttributeNodes("description");
        return this;
    }

    //rest of the with methods

    @Override
    public List<Car> build(int carId) {
        List<CarEntity> entities = em.createQuery("SELECT c FROM dbo.Car c WHERE c.id = :carId")
                .setHint("javax.persistence.fetchgraph", eg)
                .getResultList();
        return //convert list of CarEntity to Car and return list;
    }
}

And I call the repo like this:

List<Car> cars = repo.getCar().withName().withDescription().build(1);

But when I run this I get the following error:

org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.hql.internal.ast.QuerySyntaxException: dbo.Car is not mapped [SELECT c FROM dbo.Car c WHERE c.id = :carId]; nested exception is java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: dbo.Car is not mapped [SELECT c FROM dbo.Car c WHERE c.id = :carId]
    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:384)
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:246)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:488)
    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59)
    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
    at com.sun.proxy.$Proxy225.build(Unknown Source)
    at com.test.CarService.getCarById(CarService.java:118)
    at com.test.CarController.getCarById(CarController.java:34)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:240)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:96)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: dbo.Car is not mapped [SELECT c FROM dbo.Car c WHERE c.id = :carId]
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1679)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1608)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:294)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:347)
    at com.sun.proxy.$Proxy147.createQuery(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298)
    at com.sun.proxy.$Proxy147.createQuery(Unknown Source)
    at com.test.JpaCarRepository.build(JpaCarRepository.java:141)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
    ... 91 more
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: dbo.Car is not mapped [SELECT c FROM dbo.Car c WHERE c.id = :carId]
    at org.hibernate.hql.internal.ast.QuerySyntaxException.generateQueryException(QuerySyntaxException.java:79)
    at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:103)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:218)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:142)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:115)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:76)
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:150)
    at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:302)
    at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:240)
    at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1894)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:291)
    ... 112 more
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: dbo.Car is not mapped
    at org.hibernate.hql.internal.ast.util.SessionFactoryHelper.requireClassPersister(SessionFactoryHelper.java:171)
    at org.hibernate.hql.internal.ast.tree.FromElementFactory.addFromElement(FromElementFactory.java:91)
    at org.hibernate.hql.internal.ast.tree.FromClause.addFromElement(FromClause.java:76)
    at org.hibernate.hql.internal.ast.HqlSqlWalker.createFromElement(HqlSqlWalker.java:321)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3687)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:3576)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:716)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:572)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:309)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:257)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:262)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:190)
    ... 120 more

What am I doing wrong?

Edit 1: I tried changing my query to:

@Override
public List<Car> build(int carId) {
    List<CarEntity> entities = em.createQuery("SELECT c FROM CarEntity c WHERE c.id = :carId")
            .setHint("javax.persistence.fetchgraph", eg)
            .getResultList();
    return //convert list of CarEntity to Car and return list;
}

And now I get:

Caused by: org.hibernate.QueryException: Not all named parameters have been set: [id] [SELECT c FROM CarEntity c WHERE c.id = :carId]
    at org.hibernate.internal.AbstractQueryImpl.verifyParameters(AbstractQueryImpl.java:391)
    at org.hibernate.internal.AbstractQueryImpl.verifyParameters(AbstractQueryImpl.java:373)
    at org.hibernate.internal.AbstractQueryImpl.applyEntityGraphQueryHint(AbstractQueryImpl.java:1048)
    at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:604)
    at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:483)
    ... 100 more

Edit 2: So I fixed the above issue by doing this:

@Override
public List<Car> build(int carId) {
    List<CarEntity> entities = em.createQuery("SELECT c FROM dbo.Car c WHERE c.id = :carId")
            .setHint("javax.persistence.fetchgraph", eg)
            .setParameter("id", carId)
            .getResultList();
    return //convert list of CarEntity to Car and return list;
}

But unfortunately I don't think the builder is actually working because when I removed withDescription() from my query I still got back an entity with the description field populated.

How do I get it to only retrieve the attributes I specify?

Your **build()** method returns the **Car** entity object. Since it returns the entire car data object, it has all the data fields as in database. If you want to retrieve only the attributes you specify, you need to pass the data object to **build()** method along with the **Id** you already passing. Once you done with it, you change your HQL query to accommodate your attribute into it. I hope I understood your question right. Let me know if thats what you intended to do. — Rahul Raj, Jun 26 '17 at 03:08
@RahulRaj No the **build()** returns the `Car` business object, as you can see in the code above the `CarEntity` object is a separate object. The build method fetches the `CarEntity` object and then converts it to a business object before returning. Can you show an example of what you mean because I'm not following what you mean by pass in the data object. — Richard, Jun 26 '17 at 03:17
okay I understood that part. May I know whether you want your **build()** method to retrieve attributes that you specify? — Rahul Raj, Jun 26 '17 at 03:57
@RahulRaj I want to retrieve the car entity object ONLY with the attributes I specify with my `with` methods. So if I say `repo.getCar().withName().build(1)` then it should only return the Cars in the table with an id of 1 and only return the id and name attributes. The rest of the attributes (description, model, make, etc) should be null because they weren't fetched — Richard, Jun 26 '17 at 04:16
One more thing to clear is : **setHint("javax.persistence.fetchgraph", eg)** whether this query hint you passing is to set query properties (that you want only results that comprise of certain columns)? Asking this because, I haven't used entitygraph before. Let me know. — Rahul Raj, Jun 26 '17 at 06:47
You have a query with parameter `carId` yet are setting parameter `id`; perhaps you should set the right parameter (typo in your post, or in your code?). Then you debug what is actually set in the EntityGraph, then you look at the actual SQL invoked ... — Neil Stockton, Jun 26 '17 at 06:54
Also you seem to think that if a field is not in your entity graph then it won't be fetched; wrong. An entity graph tells the provider what fields it definitely should include. It doesn't provide a way of excluding fields — Neil Stockton, Jun 26 '17 at 07:12
@NeilStockton No that is the correct parameter to be set, I am fetching the correct cars from the table and am just facing an issue with excluding parameters. So is what I'm trying to do impossible with jpa? If so, is there any way to achieve what I want? — Richard, Jun 26 '17 at 12:40
If " that is the correct parameter to be set" then there is a typo in what you post here. As for the second point ... well the JPA spec says that if you specify `javax.persistence.fetchgraph` then those fields will be fetched. It doesn't prevent your JPA provider from fetching others. Some JPA providers take what you have specified as gospel (DataNucleus JPA in my experience), whilst others (Hibernate, EclipseLink) add on other fields (typically all basic fields) regardless of your presumed intent. — Neil Stockton, Jun 26 '17 at 12:58

JPA Entity Graph using Builder pattern

0 Answers0