Mapping entity to pojo with aggregation with Hibernate

StackOverflow https://stackoverflow.com/questions/18194087

题

I'm trying to create a list of POJOs from a NamedQuery that accesses an existing entity using Hibernate. I want to total the values in a mapped object into a "summary record" to use in a reporting structure of sorts, which is detailed below as "SummaryReportRollup". I tried rolling up these Headers programmatically, but there are so many that the performance was dreadful.

Here are my entities, including the mappings and excluding getters/setters/methods/un-important fields. SummaryReportRollup is defined at the bottom: 

@Entity
@Table(name = "header")
@SequenceGenerator(name="header_seq", sequenceName="header_seq", allocationSize=1)
public class Header implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="header_seq")
    @Column(name = "head_id", insertable = true, updatable = false)
    private Long id;

    @OneToMany(fetch = FetchType.EAGER, cascade={CascadeType.ALL})
    @JoinColumn(name="head_id")
    private List<DetailLineItem> detailLineItems;

    @Column(name = "location", insertable = true, updatable = false)
    private String location;

    @Column(name = "proj_year_month", insertable = true, updatable = false)
    private String projectionYearMonth;

    /* ... getters and setters ... */
}


@Entity
@Table(name = "detail")
@SequenceGenerator(name="detail_seq", sequenceName="detail_seq", allocationSize=1)
public class DetailLineItem implements Cloneable, Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="detail_seq")
    @Column(name = "detail_id")
    private Long id;

    @ManyToOne
    @JoinColumn(name="head_id", unique=false, nullable=false)
    @JsonIgnore
    private Header header;

    @ManyToOne
    @JoinColumn(name="attrib_id", unique=false, nullable=false)
    private Attribute attribute;

    private Double value;
    /* ... getters and setters ... */
}

@Entity
@Table(name = "attribute")
@SequenceGenerator(name="attribute_seq", sequenceName="attribute_seq", allocationSize=1)
public class Attribute implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="attribute_seq")
    @Column(name = "attrib_id", insertable = false, updatable = false)
    private Long id;

    @Column(name = "name", insertable = false, updatable = false)
    private String name;

    @Column(name = "mandatory_in", insertable = false, updatable = false)
    private char mandatoryIndicator;

    @Column(name = "negative_in", insertable = false, updatable = false)
    private char negativeIndicator;

    @Column(name = "decimal_in", insertable = false, updatable = false)
    private char decimalIndicator;

    /* ... getters and setters ... */
}

public class SummaryReportRollup {

    private String projectionYearMonth;
    private Attribute attribute;
    private Double value;
    /* ... getters and setters ... */
}

Here is my named query to populate SummaryReportRollup ...

    @NamedQuery(name = "findSummaryReportRollups", query = "select new SummaryReportRollup(h.projectionYearMonth, h.detailLineItems.attribute, sum(h.detailLineItems.value))  from Header h " +
         " where location in (:locations) group by projectionYearMonth, detailLineItems.attribute ")

This is the error I receive from Hibernate ...

ERROR: HHH000177: Error in named query: findSummaryReportRollups
Throwable occurred: org.hibernate.QueryException: illegal attempt to dereference collection [header0_.head_id.detailLineItems] with element property reference [attribute] [select new SummaryReportRollup(h.projectionYearMonth, h.detailLineItems.attribute, sum(h.detailLineItems.value))  from com.rac.projections.domain.Header h  where location in (:locations) group by projectionYearMonth, detailLineItems.attribute ]
    at org.hibernate.hql.internal.ast.tree.DotNode$1.buildIllegalCollectionDereferenceException(DotNode.java:68)
    at org.hibernate.hql.internal.ast.tree.DotNode.checkLhsIsNotCollection(DotNode.java:550)
    at org.hibernate.hql.internal.ast.tree.DotNode.resolve(DotNode.java:234)
    at org.hibernate.hql.internal.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:118)
    at org.hibernate.hql.internal.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:114)
    at org.hibernate.hql.internal.ast.tree.DotNode.resolveSelectExpression(DotNode.java:660)
    at org.hibernate.hql.internal.ast.HqlSqlWalker.resolveSelectExpression(HqlSqlWalker.java:893)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:2079)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.constructor(HqlSqlBaseWalker.java:2373)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:2146)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectExprList(HqlSqlBaseWalker.java:2016)    
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectClause(HqlSqlBaseWalker.java:1451)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:571)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:299)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:247)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:248)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:183)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:105)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:80)
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:168)
    at org.hibernate.internal.SessionFactoryImpl.checkNamedQueries(SessionFactoryImpl.java:1032)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:506)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1750)
    at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:94)
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:905)
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:890)
    at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:74)
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:225)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:308)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1477)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1417)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:398)
    at org.springframework.beans.factory.BeanFactoryUtils.beansOfTypeIncludingAncestors(BeanFactoryUtils.java:275)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.detectPersistenceExceptionTranslators(PersistenceExceptionTranslationInterceptor.java:139)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.<init>(PersistenceExceptionTranslationInterceptor.java:79)
    at org.springframework.dao.annotation.PersistenceExceptionTranslationAdvisor.<init>(PersistenceExceptionTranslationAdvisor.java:70)
    at org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor.setBeanFactory(PersistenceExceptionTranslationPostProcessor.java:99)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeAwareMethods(AbstractAutowireCapableBeanFactory.java:1439)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1408)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:710)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:410)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:84)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:1)
    at org.springframework.test.context.TestContext.loadApplicationContext(TestContext.java:280)
    at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:304)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:109)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:321)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:220)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:301)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:303)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Is this the wrong approach? What is it that I'm doing wrong here?

Sorry for the long post - I appreciate your help!

有帮助吗？

解决方案

To fix "illegal attempt to dereference collection" exception you need to create alias for your detailLineItems and then use it in your projection constructor

Try Modifying your query as 

@NamedQuery(name = "findSummaryReportRollups", query = "select new SummaryReportRollup(h.projectionYearMonth, detailLineItems.attribute, sum(detailLineItems.value))  from Header h inner join h.detailLineItems detailLineItems " +
         " where location in (:locations) group by projectionYearMonth, detailLineItems.attribute ")
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