Hi,
when I write HQL queries, I always have to type the property names explicitly, something like

from Person person where person.age = 30

if I want to change the name of the age property, I have to change it in the HQL string as well. (Actually when I create HQL strings I use some home made dictionary for getting the property names, but I still have to maintain the dictionary.)

So my question is, is it possible through reflection to get the path name to some property? So that I could do

<Some nice reflectionFramework>.getPathOfProperty(person.getAge())

?


Using hbn 3.2 and annotations.

thanks!

That is one confusing question :D

You want to pass the getter method and see what field is backed by that method? I can't even imagine a way to do that. Or is person.getAge() supposed to return somethign else?

Thanks, you understand my question, even though it was quite unclear I agree :)

To be precise, what I want is not the backing field, but the property, isnt Hibernate referencing the property name rather than the backing field in HQL?

So what I basically want is a function that gives me the answer to this question:
"what is the path of the property that is represented by this getter?"

By doing:

Person person = new Person();
String thePath = theFunctionIwant( person.getAge() )

thePath would contain "Person.age". (I know it is impossible this way, since the getAge() would return an int or something, so what I really need is a way to reference that this is a property...)

Then I could construct my HQL without having to duplicate the information that age is a property of Person through some private dictionary.

Or am I missing out on some basic concept in Hibernate here? If not, I would believe that other people would be bothered by the need for duplicating information as well?

Thanks again!

I suppose that you can lurk through the Configuration metadata, but I've never done that myself. It certainly sounds like you would benefit more from building Critieria queries, since they are a more object oriented way to build queries, especially dynamically generated ones.

Now that I've reread your post, since you are using annotations, you can use reflection to get the annotation metadata. Again, I've no experience with that, but I've seen several exaamples on the web.

Thanks for the input! I have tried using the Criteria API, more preciescely the "Example" class, but it turns out that for some reason you cannot query PK through that.
I will have a look at what is possible through annotations + reflection then.

I think that what you want is currently impossible. If I understand it correctly you would like the equivalent of the .class notition but then for methods: a method reference. This does not currently exist in Java (sadly enough) and is part of the debate for Java 7.
Related to this is the Java 7 discussion for first-class "properties"; property references would fill this need too.

Many people have the same problem you see: having Java properties or methods referred to within strings hides them from refactoring and compiler error checking. Most frameworks have problems with this but sadly enough it looks like it will take quite some time before Java aquires this ability..