Hi,

I have 2 class hierarchies like this:
Definition
--Factor
--Status
Item
--FactorItem
--StatusItem

Definition and Item are abstract mapped classes and all of the child classes are mapped to their own tables. The class Definition contains a collection of Item and Item contains a reference to its Definition. What this means is, a Factor contains FactorItems and Status contains StatusItems.

I'm having a problem with the placement of the many-to-one/one-to-many relations. I tried putting Definition in Item and I provided a getter with the return type Definition. I had an exception with Hibernate, so I tried making the getter in Item abstract and I implement the getter in FactorItem and StatusItem, but the return type is still Definition. I still get the Hibernate exception.

I don't really know what the problem is. Perhaps I'm implementing my inheritance incorrectly? Can anyone help?

Hibernate version:
3.2

Mapping documents:

@MappedSuperclass
public abstract class Definition extends BaseObject {

private List<Item> items;

protected Definition() {}

@OneToMany(mappedBy="definition")
public List<Item> getItems() {
return items;
}
}

@Entity
public class Factor extends Definition {

protected Factor() {}

}

@Entity
public class Status extends Definition {

protected Status() {}

}

@MappedSuperclass
public abstract class Item extends BaseObject {

protected Item() {}

public abstract Definition getDefinition();

}

@Entity
public class StatusItem extends Item {

private Status definition;

protected StatusItem() {}

@Override
@ManyToOne( cascade = {CascadeType.PERSIST, CascadeType.MERGE} )
public Definition getDefinition() {
return definition;
}

void setDefinition(Status definition) {
this.definition = definition;
}
}
@Entity
public class FactorItem extends Item {
private Factor definition;

private FactorItem() {}

@ManyToOne( cascade = {CascadeType.PERSIST, CascadeType.MERGE} )
public Definition getDefinition() {
return definition;
}

void setDefinition(Factor definition) {
this.definition = definition;
}

}

And this is the spring/hibernate configuration file:

<beans>
<bean id="transactionManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="sessionFactory">
<ref local="sessionFactory" />
</property>
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">
org.hibernate.dialect.OracleDialect
</prop>
</props>
</property>
<property name="annotatedClasses">
<list>
<value>ce.bo.BaseObject</value>
<value>ce.bo.Definition</value>
<value>ce.bo.Factor</value>
<value>ce.bo.Item</value>
<value>ce.bo.FactorItem</value>
</list>
</property>

</bean>

<bean id="FactorDao" class="ce.dao.hibernate.CEDaoHibernate" abstract="false" singleton="true">
<constructor-arg>
<value>ce.bo.Factor</value>
</constructor-arg>
<property name="sessionFactory">
<ref local="sessionFactory" />
</property>
</bean>

<bean id="FactorItemDao" class="ce.dao.hibernate.CEDaoHibernate" abstract="false" singleton="true">
<constructor-arg>
<value>ce.bo.FactorItem</value>
</constructor-arg>
<property name="sessionFactory">
<ref local="sessionFactory" />
</property>
</bean>
</beans>

Full stack trace of any exception that occurs:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'CETestDBTarget' defined in class path resource [applicationContextTestDB.xml]: Cannot resolve reference to bean 'FactorDao' while setting bean property 'FactorDao'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'FactorDao' defined in class path resource [hibernateObjects.xml]: Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [hibernateObjects.xml]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: @OneToOne or @ManyToOne on ce.bo.FactorItem.definition references an unknown entity: ce.bo.Definition
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'FactorDao' defined in class path resource [hibernateObjects.xml]: Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [hibernateObjects.xml]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: @OneToOne or @ManyToOne on ce.bo.FactorItem.definition references an unknown entity: ce.bo.Definition
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [hibernateObjects.xml]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: @OneToOne or @ManyToOne on ce.bo.FactorItem.definition references an unknown entity: ce.bo.Definition
Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on ce.bo.FactorItem.definition references an unknown entity: ce.bo.Definition
at org.hibernate.cfg.FkSecondPass.doSecondPass(FkSecondPass.java:40)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:288)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1205)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:871)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:797)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:901)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:870)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:393)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:257)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:168)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:226)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:115)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:798)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:589)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:389)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:257)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:168)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:226)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:115)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:798)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:589)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:389)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:257)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:168)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:254)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:332)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:92)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:77)
at org.springframework.test.AbstractSpringContextTests.loadContextLocations(AbstractSpringContextTests.java:130)
at org.springframework.test.AbstractDependencyInjectionSpringContextTests.loadContextLocations(AbstractDependencyInjectionSpringContextTests.java:224)
at org.springframework.test.AbstractSpringContextTests.getContext(AbstractSpringContextTests.java:110)
at org.springframework.test.AbstractDependencyInjectionSpringContextTests.setUp(AbstractDependencyInjectionSpringContextTests.java:192)
at junit.framework.TestCase.runBare(TestCase.java:128)
at org.springframework.test.ConditionalTestCase.runBare(ConditionalTestCase.java:69)
at junit.framework.TestResult$1.protect(TestResult.java:110)
at junit.framework.TestResult.runProtected(TestResult.java:128)
at junit.framework.TestResult.run(TestResult.java:113)
at junit.framework.TestCase.run(TestCase.java:120)
at junit.framework.TestSuite.runTest(TestSuite.java:228)
at junit.framework.TestSuite.run(TestSuite.java:223)
at org.junit.internal.runners.OldTestClassRunner.run(OldTestClassRunner.java:35)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:38)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)

I read the inheritance/polymorphism chapter a bit more thoroughly and I realize that what I'm trying to do is probably not possible. I don't have table for the superclasses, so it looks like I would use the implicit polymorphism, but I wanted to use the generated Id. I will have to consider if I want to create a table for the superclass which only contains the id.