I have an Interceptor which has a flushDirty() which calls a static method in another class that does work based on old/new values of the object. Ideally, the code that I'm calling should not know anything about Hibernate or the names of the properties mentioned in the mapping files. However, flushDirty() receives as arguments: the current state of the object, a list of old values, a list of new values, and a list of property names. I can't pass the list of old values to what I'm calling, because it's mapping-dependent.

I have come up with 2 possible solutions:
1) I find some way to reconstuct the old object from the list of properties and then call myMethod(oldObject, newObject). I suspect that creating the new object will cause problems in the session, because I really don't want the object to be connected. It's just there to refer to the original state. Also, is there a way to set the properties of persisted objects directly? Something like setProperty(object, property, value)?

2) I put a method in my object that returns a DTO that describes what has been modified and I call myMethod(object). Then, myMethod will get the DTO from the object and work on that. For this to work, I need to have a way to get the modified attributes for an arbitrary object, as well as their old and new values (I know how to get the last one :) ).

Any help would be appreciated. I'm leaning towards the 2nd solution, but any solution that works is infinitely better than one I have now.

Well I don't really get why passing an object containing the values would be more "mapping dependant" than passing the arrays, however ...

For 1, you can use Reflection or if you want it more easily, something like Jakarta Beanutils. The second approach sounds really overcomplicated to me, in fact you do have every Information you need in the flushDirty method, don't you?

Well I have some access="field" properties that I don't want to expose to anyone. i.e. The object exposes a slightly different API than that seen by Hibernate. I want the class that I'm calling to deal with something that looks like the object, not the properties mentioned in the mapping files.



Reflection would only work for properties that are access="property", right?

As you say, the second option may be a a bit complicated. However, it should be a straighforward thing to ask an object if it has been modified, what has been modified, and how it was modified (old/new value). These are common questions to ask of an object, so I'm sure that the answers can be provided by Hibernate. I just don't know how. :)

Is it safe for me to poke around in EntityEntry to get the info that I need?



Then, use entityEntry.loadedState and entityEntry.deletedState.

I'd prefer not to have to poke this deeply if at all possible.

Hibernate use cglib/reflexion to access fields.

No it's not safe and may change (especially in the 2.2 branch).

What do you people think about adding the ability to get modification info about an object? It could be something as simple as:


Basically, I'm asking if it was a design decision to exclude this functionality or if it's just something that hasn't been added yet. If it's the latter, I'll add it to JIRA.

Yes, there are good reasons for not exposing this.

There are some borderline cases where semantics of isModified() would be doubtful.