Hi All,
I'm trying to understand the recursive mapping given in "Hibernate in Action" and not able to persist the Category object. Please help me in understanding that the mistake I'm making here.
Category.hbm.xml
Code:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Sep 22, 2011 3:30:35 PM by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping>
<class name="org.learning.hibernate.Category" table="CATEGORY">
<id name="id" type="int">
<column name="ID" />
<generator class="assigned" />
</id>
<many-to-one name="parent" class="org.learning.hibernate.Category" fetch="join">
<column name="PARENT" />
</many-to-one>
<set name="children" table="CATEGORY" inverse="false" lazy="true">
<key>
<column name="ID" />
</key>
<one-to-many class="org.learning.hibernate.Category" />
</set>
</class>
</hibernate-mapping>
Category.java
Code:
import java.util.HashSet;
import java.util.Set;
public class Category {
private int id;
private Category parent;
private Set<Category> children = new HashSet<Category>();
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Category getParent() {
return parent;
}
public void setParent(Category parent) {
this.parent = parent;
}
public Set<Category> getChildren() {
return children;
}
public void setChildren(Set<Category> children) {
this.children = children;
}
public void addChildren(Category child){
if(child.getParent()!=null){
child.getParent().getChildren().remove(child);
}
child.setParent(parent);
children.add(child);
}
}
So, if are already aware of this example given in the book (Hibernate in action), then this setup is almost the same as given.
Now, my persisting logic is as below and this is where, I think the flaw is
Code:
Session session = HibernateUtil.currentSession();
session.beginTransaction();
Category electronics = new Category();
Category tv = new Category();
Category discPlayer = new Category();
tv.setId(2);
tv.setParent(electronics);
discPlayer.setId(3);
discPlayer.setParent(electronics);
electronics.setId(1);
electronics.addChildren(tv);
electronics.addChildren(discPlayer);
session.save(electronics);
session.getTransaction().commit();
I'm getting the below exception
Code:
org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1
at org.hibernate.jdbc.Expectations$BasicExpectation.checkBatched(Expectations.java:85)
at org.hibernate.jdbc.Expectations$BasicExpectation.verifyOutcome(Expectations.java:70)
at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:47)
at org.hibernate.persister.collection.AbstractCollectionPersister.recreate(AbstractCollectionPersister.java:1206)
at org.hibernate.action.CollectionRecreateAction.execute(CollectionRecreateAction.java:58)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:265)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:188)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133)
at org.learning.hibernate.tests.TestHibernateExamples.testCategory(TestHibernateExamples.java:130)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
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.junit.runners.ParentRunner.run(ParentRunner.java:236)
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)
Upong debugging, I see its failing at session.getTransaction().commit();
and the Hibernate logs shows
Hibernate:
/* insert org.learning.hibernate.Category
*/ insert
into
LEARN.CATEGORY
(PARENT, ID)
values
(?, ?)
Hibernate:
/* create one-to-many row org.learning.hibernate.Category.children */ update
LEARN.CATEGORY
set
ID=?
where
ID=?
Now, I know that Hibernate does not do automatic association management as EJB does, but what is the proper way of persisting the Category.
Please advise.
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