Associated class for one-to-one relations

kjrabe · **Joined:** Thu Dec 01, 2005 3:18 pm **Posts:** 6

I am using the latest version of the Hibernate tools (3.1b4) and am trying to have my generated POJO to have the following set method for one-to-one relations:

Code:

public void setFoo(Foo foo) {
    this.foo = foo;
    if (foo.getBar() != this)
        foo.setBar(this);
}

With a many-to-one and a one-to-many relationship I am already able to generate code that looks like:

Code:

public void addToFoos(Foo aFoo) {
    getFoos().add(aFoo);
    aFoo.setBar(this);
}

I can generate the above code by doing various comparisons ant iterations using the mapped persistent class. Unfortunately there does not appear to be a similar mechanism for one-to-one relationships.

max · **Posted:** Tue Apr 04, 2006 9:54 pm

what is your starting point ?

database or mapping files ? (reverse engineering or basic code generation ?)

Reverse engineering does not build up one-to-one's so you will never get such things created in the metamodel.

mapping files (ofcourse) support one-to-one and then my question is what is the problem you are having ?

btw. if your addToFoos templates are good then please submit them to jira since it is generally usefull.

kjrabe · **Joined:** Thu Dec 01, 2005 3:18 pm **Posts:** 6

I'm starting from mapping files. We do pretty much everything from the hbm.xml files.

Unfortunately I'm not yet at liberty to provide any source code for the addToFoos. I expect that this will change sometime in the near future, at which point I can provide a patch/template code.

max · **Posted:** Wed Apr 05, 2006 6:03 am

so if you start from mapping files what is the actual problem ?

kjrabe · **Joined:** Thu Dec 01, 2005 3:18 pm **Posts:** 6

The problem is that I can't figure out how to get the corresponding field name. At source code generation runtime, the only information that I can find is the name of the other class in the one-to-one relationship.

Running through the Eclipse debugger, I can't find a path from the information I have about the property for the OneToOne object to find out the name of the opposing field.

I haven't found any mechanism to work from a class name as a String back to either a PersistentClass or a RootClass object. If I could get to either of these, this would be reasonably straightforward.

max · **Posted:** Wed Apr 05, 2006 11:18 am

you will need to go to the "other side" and find a matching OneToOne via getReferencedEntityName.

How did you find the "opposite" side of the ManyToOne/OneToMany ?

kjrabe · **Joined:** Thu Dec 01, 2005 3:18 pm **Posts:** 6

I had found getReferencedEntityName, but couldn't figure out how to go from that String to a more useful object like a PersistentClass or even better a RootClass.

I was only concerned about one side of the ManyToOne/OneToMany relationship (i.e. that of the parent) and was able to do that by looking at the columns of the associated PersistentClass to determine which column was the relevant one. I am currently trying to determine whether I can actually post that code.

max · **Posted:** Wed Apr 05, 2006 2:38 pm

theOtherSide = $cfg.getClassMapping(entityName);