I found a solution to deproxy a class using standard Java and JPA API. Tested with hibernate, but does not require hibernate as a dependency and should work with all JPA providers.
Onle one requirement - its necessary to modify parent class (Address) and add a simple helper method.
General idea: add helper method to parent class which returns itself. when method called on proxy, it will forward the call to real instance and return this real instance.
Implementation is a little bit more complex, as hibernate recognizes that proxied class returns itself and still returns proxy instead of real instance. Workaround is to wrap returned instance into a simple wrapper class, which has different class type than the real instance.
In code:
class Address {
public AddressWrapper getWrappedSelf() {
return new AddressWrapper(this);
}
...
}
class AddressWrapper {
private Address wrappedAddress;
...
}
To cast Address proxy to real subclass, use following:
Address address = dao.getSomeAddress(...);
Address deproxiedAddress = address.getWrappedSelf().getWrappedAddress();
if (deproxiedAddress instanceof WorkAddress) {
WorkAddress workAddress = (WorkAddress)deproxiedAddress;
}