Trouble making one-to-one associations

jarkko · **Joined:** Thu Oct 23, 2003 9:50 am **Posts:** 4

Hello,
I'm having trouble deploying objects containing one-to-one associations. I've used one-to-many(collection) types of assocation with no fuss, this is a first time i'm playing with one-to-one ones.

Having the following xdoclet in my object works just fine. Not he use of class = "fi.jab.poc.Role" which causes no problem.

Code:

/**
    * @hibernate.set order-by = "role_id" cascade = "all"
    * @hibernate.collection-key column = "user_id"  
    * @hibernate.collection-one-to-many class = "fi.jab.poc.Role" 
    */
   public Collection getRoles() {
      return roles;
   }

But when i'm trying to use the same class (which is also Hibernated object) with one-to-one i've to make it implement Serializable otherwise there'll be some deployment time exceptions thrown from Binder.getTypeFromXML-method.

Here's the xdoclet configuration for the offending part:

Code:

   /**
    * @return
    * @hibernate.property 
    * @hibernate.one-to-one 
    */
   public Person getPerson() {
      return person;
   }

Code:

17:11:10,011 INFO  [Binder] Mapping class: fi.jab.poc.LogItem -> JAB_LOGITEM
17:11:42,668 ERROR [Configuration] Could not compile the mapping document
net.sf.hibernate.MappingException: Could not interpret type: fi.jab.poc.Person
   at net.sf.hibernate.cfg.Binder.getTypeFromXML(Binder.java:788)
   at net.sf.hibernate.cfg.Binder.bindValue(Binder.java:354)
   at net.sf.hibernate.cfg.Binder.propertiesFromXML(Binder.java:891)
   at net.sf.hibernate.cfg.Binder.bindRootClass(Binder.java:294)
   at net.sf.hibernate.cfg.Binder.bindRoot(Binder.java:1095)
   at net.sf.hibernate.cfg.Configuration.add(Configuration.java:230)
   at net.sf.hibernate.cfg.Configuration.addInputStream(Configuration.java:252)
   at net.sf.hibernate.cfg.Configuration.addResource(Configuration.java:273)
   at net.sf.hibernate.jmx.HibernateService.buildSessionFactory(HibernateService.java:160)
   at net.sf.hibernate.jmx.HibernateService.start(HibernateService.java:131)
   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:324)
   at org.jboss.mx.capability.ReflectedMBeanDispatcher.invoke(ReflectedMBeanDispatcher.java:284)
   at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:546)
   at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:976)
   at $Proxy14.start(Unknown Source)

Maybe i'm just missing something, can someone point me to proper documentation/examples?
Or is it neccaccery for one-to-one referenced object to be either serializable or one of the other types mentioned in TypeFactory.hueristicType (maybe a typo?)?

emmanuel · **Posted:** Thu Oct 23, 2003 12:20 pm

Quote:

Maybe i'm just missing something, can someone point me to proper documentation/examples?
Or is it neccaccery for one-to-one referenced object to be either serializable or one of the other types mentioned in TypeFactory.hueristicType (maybe a typo?)?

Person must be serializable and mapped.[/quote]

gavin · **Posted:** Thu Oct 23, 2003 1:43 pm

Why should it be serializable?

emmanuel · **Posted:** Thu Oct 23, 2003 4:17 pm

gavin wrote:

Why should it be serializable?

Because I'm wrong ;-)
I mismatch component class used as a composite identifier requirements with mapped class requirements.

jarkko, Person class implements Type interface ? Is there a reason ?
Havea closer look at Javadoc of Type AND UserType. Have a look at section 4.2.4 of the reference guide.

Your mapping fails because Hibernate cannot instanciate Person (Person.newInstance()). Does Person have a default (no args) constructor ?[/quote]

jarkko · **Joined:** Thu Oct 23, 2003 9:50 am **Posts:** 4

gavin wrote:

Why should it be serializable?

Actually the real question i'm trying to ask is that why it's working when Person is placed inside a Collection (in the many-to-one-case) and why it should be modified when used "directly" in the one-to-one-case?

Any reason for this one or am i still mislooking something?

emmanuel · **Posted:** Thu Oct 23, 2003 5:32 pm

Code:

   /**
    * @return
    * @hibernate.property 
    * @hibernate.one-to-one 
    */
   public Person getPerson() {
      return person;
   }

Forget what I said, it was totally wrong. The broken part is due to the @hibernate.property tag, not the one-to-one.

Property has to be an Hibernate type (basic, UserType, ...)
A serializable class can be mapped on the Hibernate SerializableType.

I don't understand why you need to map person as a Property AND a one-to-one.

jarkko · **Joined:** Thu Oct 23, 2003 9:50 am **Posts:** 4

I made some changes to the xdoclet to make it more obvious what i was trying to reach:

Code:

/**
    * @hibernate.property  column = "person_id" 
    * @hibernate.one-to-one  class = "fi.jab.poc.Person" 
    */
   public Person getPerson() {
      return person;
   }

And here's the Hibernate mapping generated from it:

Code:

        <property
            name="person"
            type="fi.jab.poc.Person"
            update="true"
            insert="true"
            column="person_id"
        />

        <one-to-one
            name="person"
            class="fi.jab.poc.Person"
            cascade="none"
            outer-join="auto"
            constrained="false"
        />

So it seems (haven't tested it) that to archieve what i want i need the following xdoclet:

Code:

   /**
    * @hibernate.property  column = "person_id" type = "fi.jab.poc.Person"
    */

Which translates to

Code:

    <property
            name="person"
            type="fi.jab.poc.Person"
            update="true"
            insert="true"
            column="person_id"
        />

Maybe i was a little confused with the term "one-to-one", but thanks for the info i'll look it from the document.

jarkko · **Joined:** Thu Oct 23, 2003 9:50 am **Posts:** 4

Ah, no. If the type in property has to be HibernateType the above won't still work.

emmanuel · **Posted:** Fri Oct 24, 2003 2:39 am

If I understand you well, what you need is

Code:

 <one-to-one
            name="person"
            class="fi.jab.poc.Person"
            property-ref="person-id"
        />

This is a 2.1 beta1 and + feature.
I don't know if it is doable with xdoclet.

On 2.0.x, Person PK must match The other class PK (behavior wo property-ref).

Your mapping isn't good, You shoud not map a property and a one-to-one to the same attribute. One to one already map the attribute. Actually, I do not know how your mapping works.

Have a look at http://forum.hibernate.org/viewtopic.php?t=924804&highlight=propertyref

Remove

Code:

@hibernate.property column = "person_id"

And update your mapping with the property-ref attribute.